Singer Family Shops — Electrical Instructions — Reference guide — PDF Download

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Form 20596

(253)


            MANUAL
                    OF
      ELECTRICAL INSTRUCTIONS

                     FOR
       SINGER FAMILY SHOPS



         SINGER®

               FAMILY SEWING MACHINE MOTORS,

                   SINGERLIGHTS, CONTROLLERS,

           HAND AND FLOOR VACUUM CLEANERS,

                    FLATIRONS, FANS, Etc.





                   SINGER

                SEWING


                  MACHINE




      THE SINGER MANUFACTURING COMPANY

                *A Trade Mark of THE SINGER MANUFACTURING COMPANY

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PROPERTY OF
    THE SINGER MANUFACTURING COMPANY

This is a private and confidential communication to and for the
use of only the employees of The Singer Manufacturing Company
and its affiliated companies.  Reproduction, sale, distribution, or
publication thereof to the public is forbidden.

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PRE FACE



                      This manual contains all of the important information covering the

                   family type electrical apparatus manufactured by the Company. It is in

                  loose leaf form so that sheets giving information regarding new develop-

               ments may be added, thus keeping the book constantly up to date. It is

                  divided into several sections, as explained in the table ofcontents, and

              when additional sheets are issued they must be inserted in theproper

                     place.





                                                              (Insert in Form 20596 in place of corresponding leaf)

Rev. (1255)

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TABLE OF CONTENTS

                 This service manual is divided into several parts with each group of
            apparatus or information having a Part number and each type of group
             having a Section number. For example: PA2 Motors are in Part 4 (Motors)
             Section 4 (PA2 Motors).

  PART 1-INTRODUCTION

            Section 1-Questions and answers to help the salesman understand the answers he might
              give to customers' questions. Explanation of motor identification symbols.
           Section 2-Description of series commutator type electric motor with suggestions for
                 servicing.

  PART 2-SEWING MACHINE MOTOR APPLICATION

           Section 1-Motor Application Charts
           Section 2-Summary of Family Sewing Machine Motors
           Section 3-Belt Application Chart

  PART 3-SPECIAL APPLICATIONS OF SEWING MACHINE MOTORS

           Index for Part 3
           Section 1-Family Sewing Machines with ground connection.
           Section 2-Electrical Outfits for School Tables Nos. 409 and 410.
          Section 3-Electrical Outfits for School Tables Nos. 411 to 416 inclusive.
          Section 4-Electrical Outfits for School Tables Nos. 417, 418 and 419
          Section 5-Electrical Outfits for 64" School Tables
           Section 6-Conversions of School Tables

  PART 4-MOTORS-SERVICE PARTS CHARTS

           Section 1-BA Motors for Family Sewing Machines
           Section 2-BZ Motors for Family Sewing Machines
           Section 3-PG and PH Motors for 15-91 and 201-2 Machines
           Section 4-PA Motors for Class 301 Machine
           Section 5-Series 3 Motor for Classes 221 and 222 Machines
           Section 6-CA Motors for Classes 221 and 222 Machines
           Section 7-BR and BR-S Motors for Family Sewing Machines
           Section 8—RF Motors for Family Sewing Machines
           Section 9-BY Motors for Family Sewing Machines
           Section 10-BS Motor for 128-8 Family Sewing Machine
           Section 11-BV Motor for Class 6ó Family Sewing Machine
           Section 12-Series 4 Motor for 66-8 and 128-8 Family Sewing Machines
           Section 13-BUE Motors for Family Sewing Machines
           Section 14-BU Motors for Family Sewing Machines
           Section 15-BT Motors for Family Sewing Machines

  PART 5-LIGHTS-SERVICE PARTS CHARTS

           Section 1-Light with Lead for Class 301 Machine
           Section 2-Catalog S-4 Light
           Section 3-Catalog S-1 Spotlight
           Section 4-Light with Lead for Classes 201 and 221 Machines
           Section 5-Catalog S-5 Spotlight

Rev. (1256)                                  (Insert in Form 20596 in place of corresponding leaf)                                                      PRINTED

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TABLE OF CONTENTS — Continued




 PART 6-CONTROLLERS-SERVICE PARTS CHARTS

PART 7-VACUUM CLEANERS

         Section 1-Servicing instructions for S-3 floor type vacuum cleaner
         Section 1A-Servicing instructions for S-2 floor type vacuum cleaner
         Section 2-Servicing instructions for H-7 and H-9 hand type vacuum cleaners
         Section 3-Servicing Instructions for S-4 Floor Vacuum Cleaner

PART 8-FLATIRONS

PART 9-FANS

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MANUAL OF ELECTRICAL INSTRUCTION PART 1
Section 1, Page 1

WHEN WERE THE FIRST ELECTRIC MOTORS BUILT FOR DRIVING SEWING MACHINES?

The first electric motors for driving family sewing machines were built in 1911. Since that
time the motors and other electrical apparatus on family sewing machines have been steadily
improved, until at the present time SINGER* Electric Family Sewing Machines are the finest in
the field.

TO WHAT MACHINES CAN MOTORS BE APPLIED?

SINGER family sewing machine motors may be applied to any SINGER lock stitch family
machine having the hand attachment seat to which the motor fastens. They may also be applied
to chain stitch machines of the 24 class, either portable or cabinet styles. In later years sewing
machines have been designed especially for electric motor drive, and in these machines the
electric motor is a part of the equipment regularly furnished. Detailed charts showing the proper
motors, controllers, and SINGERLIGHTS for each of the various classes of sewing machine will
be found in Part 2 of this manual.

Fig. 1. Machine 15-90 Showing BA3 Motor and S4 SINGERLIGHT

FOR WHAT ELECTRIC POWER SUPPLIES ARE THESE MOTORS FURNISHED?

An electric motor may be obtained of the proper rating to suit almost any particular power
supply available anywhere in the world. Motors for direct current and 25 to 75 cycles alternating
current at 110 to 120 volts suit the electrical power supply prevailing in nearly all parts of the
United States, and will be supplied unless otherwise ordered.

HOW MUCH POWER DOES THE MOTOR USE?

The power required to operate motors for driving family sewing machines at full speed
varies from 40 watts to 60 watts, or approximately as much as an ordinary electric light bulb
Sewing machines are not operated continuously at high speed in the home, but are frequently
stopped, and much of the time are run at less than full speed. Under these conditions, they use
substantially less power than an ordinary 60 watt electric light bulb.

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MANUAL OF ELECTRICAL INSTRUCTION PART 1

Section 1, Page 2

HOW MUCH DOES IT COST TO OPERATE A SINGER ELECTRIC SEWING MACHINE?

It depends largely upon the cost of the current per kilowatt hour, and the length of time
the machine is used each day. For example, if the motor with its SINGERLIGHT* consumes 60
watts and is operated for 3 hours each day, it will have used 3 X 60 = 180 watt hours. If the

family with no electric refrigerator, radio, television set, or other large electrical appliance:
ay pay as much as 8c per kilowatt hour, in which case the cost of running the sewing machin
described above would be 2.16 X 8 = 17.3 or less than 18c per month.

HOW MUCH DOES IT COST TO OPERATE A SINGER FLOOR TYPE VACUUM CLEANER?

A SINGER foor vacuum cleaner consumes about 330 watts, and if used for 1 hour pe
Jay it will consume during one month 330 X 30 = 9900 watt hours, or 9.9 kilowatt hours. De
sending upon the amount of power used in the household for electrical appliances, the cost ol
unning the vacuum cleaner may vary between 40c and 80c per month.

HOW MUCH DOES IT COST TO OPERATE A SINGER HAND VACUUM CLEANER?

A SINGER hand vacuum cleaner consumes about 170 watts, and if operated for ½ hour
per day it will consume during one month 170 X 15 = 2.55 kilowatt hours. Again depending
upon the amount of power used by the customer, this may cost from 10c to 20c per month.

ARE SINGER MOTORS PERFECTLY SAFE?

They are approved by the Underwriter's Laboratories, Canadian Standards Association, and
other electrical safety agencies throughout the world. The motors, controllers, SINGERLIGHTS
and wiring are designed and built of the finest material and workmanship. Before being shipper
rom the factory, each motor is thoroughly tested to assure its safety. When any electrical devic
is not to be used for some length of time, however, it is suggested that the plug be removed from
the outlet and the electric cord be removed from the floor where it might be subject to damage.

AT WHAT VOLTAGE WILL THE MOTORS RUN SATISFACTORILY?

Every electrical power supply is furnished at a certain voltage, which may be likened to the
pressure in a water system. Every SINGER motor has a voltage stamped on its nameplate, and
the voltage of the power supply to which the motor is connected should agree with the voltage
stamped on the motor nameplate. Where a voltage range is given, the motor will operate satis-
factorily within this range. Where a single voltage is given, the motor will operate satisfactorily
within about 10% on either side of voltage stamped on the nameplate.

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MANUAL OF ELECTRICAL INSTRUCTION PART 1
Section 1, Page 5

WHAT IS A CYCLE?

A cycle is the flow of current in one direction followed by a reversal flow in the other
direction. When this happens 60 times every second, the electric power supply is known as a
60 cycle supply. This is the normal number of cycles per second, or frequency of electric supply
in the United States.

WHAT IS A VOLT?

Electricity flowing through a wire meets resistance, and pressure is necessary to make it
flow, just as water flowing through a pipe meets with friction, and pressure is necessary to keep
the water flowing. Water pressure is measured in pounds per square inch. Electrical pressure is
measured in volts.

WHAT IS AN AMPERE?

An ampere is the unit for measuring the electric current which flows through a wire.

WHAT IS A WATT?

The watt is a unit of electrical power. It measures the rate at which electrical energy is
being supplied to a circuit.

WHAT IS A KILOWATT-HOUR?

A kilowatt-hour is the quantity of electrical energy used steadily at the rate of 1000 watts
(1 kilowatt) for 1 hour. This is the basis on which electric light companies render their bills to
customers.

IS IT SAFE TO RUN THE MOTOR WITH THE BELT OFF?

This is likely to damage the motor and should be avoided. In case the motor will not start
the sewing machine, test it by taking the belt off the motor pulley and gently press the controller.
The instant the motor starts, release the controller thus preventing the motor from reaching
high speed. If the motor starts, the trouble is probably with the sewing machine and it should
be carefully lubricated and checked for tightness or damaged parts before resuming sewing.

WHAT ATTENTION DOES THE MOTOR REQUIRE?

Normally the motor requires no special attention, and it is best to leave it alone as long
as it runs satisfactorily. If it becomes noisy or slow in time, squeeze a little SINGER* Motor

Fig. 4. Showing Lubrication Tubes (A)

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MANUAL OF ELECTRICAL INSTRUCTION PART 1
Section 1, Page 6

Lubricant into each grease tube. Do not use oil, since this might run over on to the commutator,
and impair the operation of the motor. If it fails to start or run properly, the brushes probably
need renewing. Unless the customer has done this before, it would be best to bring the motor
to the nearest SINGER Shop, have new brushes installed, and learn how this should be done.
In ordinary service the brushes should last for several years before needing replacement. See
Part 1, Section 2 for more detailed instructions.

HOW DOES THE COMPANY GUARANTEE THE SINGER FAMILY SEWING MOTORS?

The Company stands back of its motors in exactly the same manner as it does with all its
other products. They are the only sewing motors made and guaranteed by a sewing machine
manufacturer.

HOW ARE FAMILY SEWING MOTORS IDENTIFIED?

It is customary to identify a particular motor type with a catalog number consisting of two
capital letters (for example BA) to indicate the general construction, followed by a number (for
example BA3) to indicate the mechanical arrangement of parts to fit certain sewing machine
applications. The voltage rating of the motor is identified by a dash number (for example
BA3-8).

There are certain exceptions to this system. BR, PG and PH motors have only the voltage
code number. In theBRS motor the "S" follows the voltage code number (for example BR-8S).
Series 3 motors are written without voltage code number, but the top of the voltage range
follows (Series 3-120).

The SS number shown on some motors is a factory identification number, and occasionally
when writing to the factory regarding motors, it may be necessary to show the SS number.

OTORR

AC. &DC.

Fig. 5. Motor Nameplate

WHAT DO THE VOLTAGE CODE NUMBERS MEAN?

The rated voltage of family sewing machine motors is indicated by a dash (-) number
suffixed to the catalog number, and values have been assigned to these dash numbers as follows
(all voltages are DC and 25 to 75 cycles AC except where noted).

-3 for 32 volts DC only -10 for 190-210 volts
-11 " 210-230 " 50 " -5 " 95-100 volts -12 " 230-250" -6
-7 100-110 -13 " (unassigned)
-8 110-120 -14 " 120-130 volts
-9 150-165 -15 " 130-145 "

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MANUAL OF ELECTRICAL INSTRUCTION PART 1
Section 2, Page 1

SERIES COMMUTATOR TYPE ELECTRICAL MOTOR

DESCRIPTION

Family type sewing machines are almost always driven by series commutator type of electric

motor. This motor consists of a stationary field which is housed in the outer frame of the motor, and
carries within it an armature mounted on a shaft which rotates in bearings and provides the me-

chanical power output of the motor.

The field core is made up of a series of sheets of thin steel, especially compounded for its
electrical properties, and stacked together to form what might appear on first glance to be a solid

piece of steel of rather peculiar shape. This shape has been carefully designed to have the neces-
sary characteristics to make a motor of proper performance. Within this field structure are found

2 coils of copper wire which carry the field current. These coils are carefully insulated so that none

of the wires can touch the steel of the field structure.

Fig. 1. Assembling Field Core and Coils of BA Motor

The armature core is likewise composed of a stack of thin electrical steel sheets, called lamin-

ations, designed for the job it must do. It usually has many slots into which coils of wire are wound.
These coils are carefully insulated so that none of the individual wires will touch the steel of the

(Rev. 955)

(insert in rorm 20570 in place of corresponding leat)

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MANUAL OF ELECTRICAL INSTRUCTION PART 1
Section 2, Page 2

armature core. The wires from these coils on the armature are connected to a commutator, which

is simply a series of copper bars arranged around the shaft. The armature shaft goes through the

armature core, and rests in bearings held by the outer frame of the motor. The armature rotates in
these bearings under the influence of the electric current and supplies mechanical power.

Fig. 2. Armature Laminations of BA3 Motor

221439

Fig. 3. Armature Core Wound commutatol

The commutator is pressed on the shaft at one end of the armature winding. It is composed of

copper bars separated from one another by sheets of mica insulation. Each armature coil is con-
nected to different bars so that the commutator acts as a switch to successively change the coil
connections as the armature revolves in the stationary field. For resume of the various types of

family sewing machine motors see Part 2, Section 2.

The brushes are small blocks of electrically conductive carbon which are pressed by the brush
springs against the bars of the commutator. These brushes are connected to the field windings in

such a way that the current from the power supply fows through one field, then through the brushes

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MANUAL OF ELECTRICAL INSTRUCTION PART 1
Section 2, Page 3

to the armature windings, then back through the brushes to the other field, and finally back to the

power supply, giving up in the process the electrical energy which makes the motor run.

Fig. 4. Brushes, Brush Springs and Screws Removed from Motor

These electrical parts, although constructed and designed to give long and satisfactory service

in the field, should not be abused. If the motor is taken apart for any reason, the electrical parts in-
side should be carefully handled to avoid damage.

Basically, all SINGER Family Sewing Motors are of this construction; that is, they consist of a

stationary field winding, an armature winding, a commutator and brushes. Beyond this the housings

for these parts and the electrical and mechanical connections of the motors vary with improvements
and application.

There are two general groups of SINGER Family Sewing Motors. There are those motors that

drive the sewing machine by means of a belt and pulleys and include the BT, BU, BR, BRS, BA, BS, BV,
BY, BZ, Ser. 3, Ser. 4, CA6, CA7 and RF4 motors. The others drive the sewing machine through

gears and include the SE, SU, PG, PH and PA motors.

CAUTION

Always operate the motor within the voltage range stamped on the motor name plate. Where

a single voltage is given on the name plate, instead of a voltage range, the motor will operate satis-
factorily within about 10% on either side of the indicated voltage. A higher voltage supply will
produce excess speed and may damage the motor. A lower voltage supply may not permit the
motor to reach normal speed.

PUtTA (Rev. 955)

(Insert in Form 20596 in place of corresponding leaf)

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PART 1
MANUAL OF ELECTRICAL INSTRUCTION.                           Section 2, Page 4
CAUTION- Continued


    When operating a motor on alternating current, not only the available voltage, but the cycles
should be within the range stamped un the name plate.

     Orders for motors, controllers and sewing lights must specify the voltage range required.

     Never apply oil or ordinary grease to the sewing machine motor. Use SINGER Motor Lubri
 cant. Entrance of oil into the motor may cause the motor to "burn out". The motor lubricant shoulc
be applied, when necessary as instructed on page 24.

     Brushes and springs should be removed and replaced as instructed on page 19. Customer:
  hould be cautioned against replacing them without proper instruction

    Caution all customers on the above matters and against "tinkering" with the motor at any
 time.




                   MOTOR TROUBLES AND CAUSES
                             (See pages 5 and 6 for Remedies)



MOTOR FAILS TO START
    Wrong connections at 3-pin terminal
                                         Loose or broken connections
     Current turned off                            In field coil
     Brushes not making contact                  At brush tube
      Controller pedal binding
                                                      In lead cord
     Sewing machine binding                      In wall plug
     Armature binding; short-circuited; damaged     At 3-pin terminal
      Motor. lubricant heavy or gummed
     Commutator dirty

      Controller resistance unit broken or burned out


 MOTOR SLOWS DOWN-FAILS TO REACH HIGH SPEED

     Voltage below that indicated on motor name-plate
      Lubricant heavy or gummed
      Pressure on presser foot too heavy
     Machine binding
     Armature binding
     Commutator is dirty or coated with oil or brushes are oil soaked


 MOTOR FAILS TO RESPOND EVENLY TO OPERATION OF CONTROLLER, THROUGHOUT SPEED
 RANGE

     Brushes not making contact
      Controller-carbon resistance unit-requires adjustment or replacement
       Controller pedal mechanism bent or broken

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MANUAL OF ELECTRICAL INSTRUCTION            PART
                                                                                            Section 2, Page 5




       MOTOR FAILS TO STOP
             Wrong connections at 3-pin terminal
              Short circuit
                 Bell crank on pedal mechanism (controller) dislocated
             Carbon resistance unit (controller) requires adjustment

       MOTOR TOO HOT

               Lubricant heavy or gummed
                Voltage above that indicated on motor name plate
                Short circuit-loose electrical connections
            Machine binding

             Armature binding
             Too much dust diccumulated in motor

       MOTOR NOISY
               Lubrication required-Do Not Use Oil

              Loose or hard brushes
                Motor not correctly seated on sewing machine
               Motor improperly assembled

              Core loose between end covers
               Excessive armature end play

       MOTOR TRANSMITS ELECTRICAL SHOCK

              Loose connections; frayed or broken wiring
                    Interior of motor is coated with carbon


                             REMEDIES FOR MOTOR DIFFICULTIES

              1. Heavy or Gummed Lubricant-

           When machine has been idle for some time, the lubricant may become heavy, preventing
          machine from reaching normal speed. To overcome a slight reduction in speed due to heavy
             lubricant, run machine unthreaded for a few minutes with presser foot raised. If lubricant has
         become gummy in sewing machine mechanism flush off with Varsol, dry with a clean cloth and
             lubricate as described in instruction book for the particular machine. Motor should be cleaned,
          wicks checked and then lubricated with SINGER Motor Lubricant. An inferior lubricant may
         become gummy even after a short period of idleness.


              2. Electrical Current Not Turned On-              Check power supply, switches, outlets and fuses.

              3. Loose or Broken Electrical Connections—
              Examine carefully all plugs and electrical connections in accordance with instructions on pages
              7 to 9 inclusive. Make sure that there are no broken wires, and that all screwed or soldered
            connections are tight.



u2xo (955)
                                                                       Unsert in Form 20596)

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MANUAL OF ELECTRICAL INSTRUCTION                               PART
                                                                                   Section 2, Page 6



 4. Motor Not Suited for Electrical Supply-
   See that the voltage of the electrical supply, and the frequency, if it is alternating current,
 are within the range stamped on motor name-plate, as instructed under, "Cautions" on page 3.

  5. Dirty Commutator-
    Check commutator for traces of carbon or grease. Commutator can easily be cleaned as in-
 structed on pages 22 and 23.

  6. Carbon Brushes Not Making Contact-
   When a brush does not make contact, it may be due to any of the following conditions:
     a. Grease or oil on contact surface of brush-Replace (see page 23).
      b. Dirt on brush-(Clean brush, brush tube and inside of end cover, as instructed on page 23).
      c. Damaged brush or brush tube-(Replace as instructed on page 24).
       J. Worn or broken brush springs-Replace (see page 24).
 7. Armature Binding-
    This condition, when it exists, can be discovered by turning motor pulley with the fingers, after
belt is removed from pulley or gears are disengaged.
     Causes of Armature binding:
     a. Motor end covers not correctly seated or secured, or motor end covers cracked.
       (See "Assembly of Motor", page 25).
     b. Lack of lubrication-The lubricant cups may be dry.

       (See "Lubrication", page 24).
      c. Brush tubes rubbing on commutator-this could occur if brush tubes are not correctly seated
         in bushing.
       (See "Brushes and Brush Tubes", page 24).
     d. Armature striking field coils.
       (See "Assembly of Motor", page 25).
     e. Fan blade rubbing against end cover or field coils.

  8. Broken Armature Wires-
    Check for breakage in fine wiring on end of armature.
       (See "Armature", page 22).

  9. Controller Parts Bent, Broken or Not Correctly Adjusted-
        (See "Controller Instructions").

 10. Binding of Sewing Machine-
      (See Adjusters Manual for particular machine).

 11. Pressure for Presser Foot Too Heavy-
       (See Instruction book for particular machine).

 12. Dust Accumulation-
       (See "Maintenance of Motor", page 22).

13. Motor Not Correctly Seated on sewing machine-
    (Check and replace motor, as instructed on pages 10 to 15).

 14. Motor Improperly Assembled-
       (See "Assembly of Motor", page 25).

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MANUAL OF ELECTRICAL INSTRUCTION PART
Section 2, Page 9

BLACK lead to connection sleeve No. 2, as shown in Fig. 11

1 3

Yellow Three-Pin
Terminal
to Controller. Plug

Black

Black White

E25240
Outlet

Fig. 11. Wiring Connections to Three-Pin Terminal Plug

necion of fleti Omit Plug lead Wilt Me OR oferin 0. 3 of terminad to cons
shown in Fig. 11.

Black White

E22600 E22599

Fig. 12. Tying Knot Fig. 13. Fastening Leads
(Outlet Plug) to Outlet Plug

The other end of each power line lead is connected to the outlet plug, as shown in Figs. 12
and 13. The two wires should be knotted together (see above) to prevent strain on connection
when plug is incorrectly pulled from outlet by grasping wire instead of plug itself. The bare leads
should be looped under the screw heads in the direction in which these screws are tightened, as
shown in Fig. 13.
For modern electric outlet plug assembly see Part 7, Section 2, Page 5.
NOTE: Since BT, BS, BV, BZ, RF4, Ser. 4 and SE Motors do not use the 3-pin terminal system,
the electrical connections are made as shown in Part 4.
•IT (955)
(Insert in Form 20596)

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MANUAL OF ELECTRICAL INSTRUCTION PART 1
Section 2, Page 10

ASSEMBLY OF MOTOR TO MACHINE
BT Motor

To assemble a BT Motor to the sewing machine attach motor to bracket by replacing screw,
(Fig. 14).
Place motor belt on machine, start it upward over bottom of hand wheel, as shown in
Fig. 14, until it touches undersideof arm shaft extension, then continue up over top of hand

E 4349

Fig. 14. Putting on the Belt

wheel. Never start the belt on over the top of the hand wheel, as the force necessary to do this
will stretch the belt considerably.
Replace belt on motor pulley and put idler pulley on top of belt.
Attach plugs to foot and knee control.
Turn on current and test motor at each of its five different speeds. If motor does not start,
remove belt from pulley and see if motor starts. Do not operate motor at full speed when discon-
nected from sewing machine. It will run much faster than intended, and is likely to damage arma-
ture windings or force top sticks out of slots in armature.

L1

E 3895
R

Fig. 15. Removing Idler Lever on BT Motor

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MANUAL OF ELECTRICAL INSTRUCTION PART 1
Section 2, Page 11

ADJUST IDLER-If idler pulley does not press on belt with
sufficient tension to take up slack in belt, more tension may be
secured by removing screw L1 and idler lever S, Fig. 15 and
moving the end of spring M1, Fig. 16 from hole 1 to hole 2.
Further tension can be obtained by moving the spring to hole 3.
Too much tension, however, will overload the motor, causing it
to run slow and overheat.

If idler pulley, does not rotate freely, remove it, clean inside
of bearing and scrape off black bearing level with face of
pulley if necessary.

NEVER OIL THE IDLER PULLEY BEARING. It is made of
material which does not require lubrication. Oil sometimes
causes it to stick.
E 3891

Fig. 16. Adjusting Tension on Idler Pulley
of BT Motor

BU, BR, BRS, BA Motors

To assemble a BU, BR, BRS or a BA
Motor to a sewing machine clean motor
bracket seat on machine in order to enable
motor bracket to slide freely up and down
when adjusting tension of belt.

Place motor bracket B, Fig. 17, with
motor, on motor bracket seat of machine.
Slide motor bracket upward as far as pos-
sible; replace and tighten screw G, Fig. 17.

While three-pin terminal block E, Fig.
17, is displaced after removing screw C, Fig.
17, connect electrical leads, as shown in
222760 Wiring Diagram, Part 4, Section 1, Page 4.
Replace terminal block E and tighten screw
Fig. 17. Replacing BR Type Motor C, Fig. 17.

(955)

(Insert in Form 20596)

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MANUAL OF ELECTRICAL INSTRUCTION PART 1
Section 2, Page 12

lead inch an diad id ou firmly over the three pins in terminal block E. Insert appliance plus on line

Adjust belt tensions as instructed on page 14.

BS, BV, BY, BZ, Ser. 4, RF4 Motors

o assemble a BS, BV, BY, BZ, Ser. 4 or RF4 Motor on a sewing machine simply fasten mot
racket with motor to motor bracket seat on machine arm and adjust belt tension, as instructe
on page 14.

SE, SU MOTORS

A piece of wire with a hook at or
nd may be inserted from below

To Motor
Yellow
wires and cable Red

SINGER Light
3- Pin Terminal- OVO and turn it slightly from side to side
until the spiral pinion meshes with
Yellow the gear on the arm shaft and the Black
motor will slip into position. Replace
the screw A, Fig. 27, page17
which fastens the motor frame in the
machine, but do not tighten it.

Remove the three insulated
thumb nuts on the three-pin terminal
block and the three brass washers
underneath them. E9557
Controller Unit

Fig. 18. Wiring Diagram for SU or SE Motors

Place the eyelets at the ends of the black leads on the centre post (2) of the three-pin terminal
block; place the eyelets at the ends of the red leads on the post nearest the red spot (3), and place
the eyelets at the ends of the yellow leads on the post nearest the yellow spot (1). See Fig. 18 for
wiring diagram.

Replace the three brass washers and three insulated thumb nuts. Fasten the three-pin terminal
block to underside of cabinet with screw.

With the knee lever held at full speed position, turn the motor frame slightly in each direction
until the point where the speed is highest is reached, then firmly tighten the screw
page 17 thus fastening the motor frame securely in position. Then replace the motor cover. 27d
the screw in the front end of the armature shaft B, Fig. 27 .

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MANUAL OF ELECTRICAL INSTRUCTION PART 1
Section 2, Page 16

DISASSEMBLY OF MOTOR FROM MACHINE

BT Motor

To remove a BT Motor from the sewing machine, reverse the procedure under "Assembly of
Motor to Machine"page 10.

BU, BR, BRS, BA Motors

The disassembly from the sewing machine of a BU, BR, BRS and a BA follows the procedure
below:

H

B

E22603

Fig. 26. Removing BR Type Motor from Machine

Remove screw C, Fig. 26, disengaging terminal block E, Fig. 26 from machine.
Disconnect motor leads from pins #2 and #3 on terminal block E, Fig. 26.
Remove screw G, Fig. 26, disengaging motor from motor bracket. Remove motor.
Remove belt from driving pulley F, Fig. 26.

BS, BV, BY, BZ, Ser. 4, RF4 Motors

To remove a BS, BV, BY, BZ, Ser. 4 or RF4 Motor from the sewing machine follow the procedure
below:
Remove screw A, Fig. 26, disengaging spotlight from arm of machine.
Remove screw H, Fig 26, disengaging motor bracket from bracket seat on machine and re-
move motor complete with motor bracket, controller and spotlight from machine.
Remove belt from driving puliey F, Fig. 26.

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