GEK±91584D, Vertical Drilling Motor, Type GE752

NOTE: If a gas torch is used, coil insulation

Machine Brazing

must be protected from heat by a non±flam-

1.

The recommended brazing current is 10,800

mable heat absorbent.

 

amperes at 1.6 volts. With silver±solder brazing

 

 

 

1. Pack absorbent around the insulation near

 

strips inserted between connections, clamp the

 

the connection and over adjacent coils.

 

brazing tongs on the connection and braze the

2.

Make sure all exposed insulation is covered

 

joint. If necessary, add additional solder to fill the

 

with a thick layer of absorbent, then heat and

 

joint and form a level surface.

 

separate the coil connections.

2.

Braze all exciting±coil connections before install-

 

 

2.

Heat the coiled frame in an oven at 150￿ C (302￿

 

ing the commutating coils.

 

F) for four hours to soften the varnish so pole

Gas Torch Brazing

 

bolts can be removed.

 

Remove the pole bolts and the coil±pole assem-

1.

Pack the coil insulation with non±flammable heat

 

 

absorbent material; e.g., interwoven glass cloth.

 

bly from the magnet frame.

 

 

 

 

 

 

 

2.

Insert the brazing strips and use a C±clamp or vi-

3.

Mark any shims for reassembly with the corre-

 

se±grip pliers to clamp the connection surfaces

 

sponding pole when the coil(s) is installed in the

 

tightly together.

 

frame.

3.

Use a torch tip with a 0.1 in. orifice and adjust the

 

 

Coil Installation

 

torch to obtain a slightly reduced flame. As the

 

 

 

brazing strips melt, add more solder to fill the

Procedure for New Coil±Pole Assembly

 

joint and form a level surface.

4. Remove heat absorbent packing from insulation.

NOTE: Install any exciting coils and braze their

 

Use dry, compressed air and blow out the inside

connections before installing commutating

 

 

of the frame.

coils.

 

 

 

 

1.

Before installing any coil and pole, clean the pole

WARNING: Personal injury may result if prop-

 

er eye protection is not worn when cleaning

 

 

contact surface on the frame and the pole piece

 

 

with compressed air.

 

 

mounting surface.

 

 

 

 

 

 

5.

Torque the pole bolts to the values listed in Table

 

 

2.

Install the new pole and coil in the frame with any

 

3, Page 37, Standard Bolt Torque Values.

 

shims that were on the damaged coil. Use new

6. Check the polarity of the field poles:

 

washers under bolt heads. Lubricate the bolt

 

 

 

 

 

heads, threads and washers and draw the pole

 

Energize the field circuit with a battery and check

 

bolts moderately tight.

 

 

 

pole polarity with a compass, Fig. 33.

 

 

 

3.

Refer to Table 2, Page 20, to determine the cor-

7.

Insulate the connections with silicone putty and

 

rect coiled frame assembly drawings. All coil

 

wrap connections with Mylar film (30). Apply

 

connections must be brazed with silver solder,

 

glass tape and extend each taping 1/2 in. beyond

 

GE±B20A6. Use two pieces of solder (0.010 x 1

 

the bare area of the connection. Brush the con-

 

in. x 1 in.) between terminal surfaces and braze

 

nections with air±drying alkyd varnish GE±8001.

 

terminals as follows:

8. Install and connect any cables previously re-

 

 

Brazing Coil Terminals

 

moved.

 

 

NOTE: Do not flood±dip the coiled frame before

Braze the coil terminals by one of the following meth-

the cables are installed and the connections are

ods:

 

insulated.

54

Page 54
Image 54
GE GE752 manual Brazing Coil Terminals, Gas Torch Brazing