C faced motor with no rabbet inquiry

[bodaver32]

Hello,

I am wanting to replace my 2-speed 3-phase motor on my mill because the high speed side has a burnt winding and the VFD is acting funny on the low speed side.

I have located a replacement 3 phase motor locally at a good price. The C faced motor does not have the rabbet cut in it (AK dimension on motor dimension charts). The face is completely smooth.

Is this going to matter?

Thanks.

 

[Ulma Doctor]

are you mounting the motor with the c-face or does the motor have a base as well?
do the bolt holes line up?

 

[bodaver32]

Yes, I will be mounting it on the face. It is an old Index 55 mill. The holes don't line up. Mounting it would be a matter of drilling 4 new holes.

The original motor is a C face that mounts to a 1/2 plate. It is nothing fancy.

 

[Ulma Doctor]

as long as you can make the bolt circle to match precisely and have the will to tackle the job and the tooling necessary,
i say GO FOR IT!!

out of curiosity, are the shafts the same length between both motors?

 

[bodaver32]

Yes the shafts are the same length. The Index machine doesn't use an extended shaft it is about 2.25".

I was going to make a bolt hole pattern and transfer it to the mounting plate.

The old motor doesn't have a rabbet on the face, is all steel and weighs in at about 60+ pounds.

 

[Tony Wells]

A couple of ideas to consider. Can you take the end bell of the old motor off and slip it over the shaft of the new one to directly transfer the mounting holes to the new one? Can you make a 1/4" or so "centering plate" to mount on the new motor face to mimic the locating boss of the old one? I generally don't like putting the stress on the face bolts of a C-face motor.

 

[bodaver32]

Tony,

The current motor is huge is simply bolted to a flat plate with a hole in it that the shaft passes through. The pulley then attaches to the shaft on the underside of the mounting plate. The plate then slides on two rails for belt tightening purposes. There is no centering boss on it.

Attached is a photo that provides its size, unfortunately I don't have a picture of the mounting plate.