Testing a Bridgeport 6R-A Motor Without a Control Board

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I have a motor from a 6R-A Bridgeport power feed. Actually, I have most of the parts for the unit, without the control board and its enclosure. I would like to test the motor to see if it works.

The data plate says:
Boehm
BM 9838 (maybe 983B)
Spec. No. 4640
Amps 4.6
Volts 90 DC A
100 DC B

Checking the wires, from Black to Red gives 3.8 to 4.5 Ohms
From White to Green produces a slight voltage when the armature is turned by hand, but essentially no resistance.
There is no continuity to the case from any wire.

I can rig up some batteries to produce 24, 36, and maybe 48 volts DC. Could this be enough to check the motor for function? I believe that the Black and Red wires go to the armature and the White and Green wires connect to the field coils. The field coils apparently control the direction of rotation. Apparently, the controller regulated the armature separately from the field coils to control speed and direction. I only need to see if it will turn at a speed that would be expected for the voltage input.

It looks like the controller died and the prior owner(s) just removed it and left the rest of the unit hanging on the end of the table, so I have hope that the motor is good.
 
Yes you could test it with batteries- 24 volts might be enough to make it spin. You could also substitute another controller like a KB to run it if you wanted a permanent solution, I think most have provisions to power motors with field coils. KBIC-125 is one series I know has a field coil output

The field coil should measure out at some value of resistance- it might be open if it doesn't. I'd check it again.
 
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I doubt the field coils would generate voltage when I spin the armature by hand if the circuit was open which they do. I can try spinning it up faster with a drill to test.

I'm not going to be using any of the parts. I just want to pass this along to someone who needs the parts. I'll put them in the classifieds when I'm sure of the condition.
 
Yes, spin the armature with a drill motor and look at the results.
I have used this technique for DC tachometer as well.
 
I got a chance to test the motor leads again. There are two separate circuits:

The first has Red/Black wires. They measure 3.8 to 5.4 ohms resistance, and if you motor the shaft with a drill, it puts out about 40 mV DC at 600 RPM.

The second circuit has White/Green wires. 'they measure .580 kiloohms resistance. They produce about 1.5 Volts AC if you motor the shaft at 600 RPM.

If you apply 24 volts DC to the Red/Black wires, it has a large current draw, and does not try to motor the armature.

I think the controller will be necessary to test the motor.

There is no path to ground (the case) from any wire, so I believe that the motor isn't burned up.
 
You would need to apply your 24 volts dc power to both the field coils and the armature to get it to turn
-M
 
I would use 12 -24 for the field and 5 v for the armature.
Without the magnetic field from the field it will not start to spin and if it does spin and the field goes away it will more than likely spin faster and faster.
Field loss is how most DC motors damage themselves as they can spin uncontrollably.
 
sdelivery said:
I would use 12 -24 for the field and 5 v for the armature.
Without the magnetic field from the field it will not start to spin and if it does spin and the field goes away it will more than likely spin faster and faster.
Field loss is how most DC motors damage themselves as they can spin uncontrollably.
Click to expand...
I don't have a way to supply 5V DC power. I'll have to do some research on this.
 
Post the motor data plate, I might have a drive.
You can use any common battery to provide the 5 volts, without seeing the motor data plate that was a guesstimate of a low rpm voltage.
Pictures make EVERYTHING better......
Ok, maybe not , a very large woman just walked by wearing spandex pants....

Just reread your first post, I will look through the catacombs.
 
I have a Dart Controls 251-12c it appears that it could possibly run the motor.
I couldn't find enough information about the motor to make me comfortable about just trying it.16853210765642429298510881618745.jpg
 
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