Film-Tech Forum ARCHIVE: When looking for replacement motor, what does the "J" in the frame number denote?

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Posted by Brad Allen (Member # 470) on 05-22-2005, 01:52 PM:

Fried a projector motor. It has a frame number of J48.
I can find a replacement @ Grainger that has a frame of 48, and it appears it will fit. But they don't list a frame with a J in it.
Anyone know what that denotes?

Posted by Maddison Lake (Member # 2876) on 05-22-2005, 02:32 PM:

Probably a manufacturing line code? Not sure, I always order and make sure they have a return policy and if it doesn't work BACK it goes. But if its both a 48 I see no reason why it wouldn't work. Although I have seen motors that the alphabetical number is different because of a fitting type they use BUT exactly the same mechanical operation.

-ML

Posted by Mark Gulbrandsen (Member # 72) on 05-22-2005, 08:26 PM:

I would take the bad motor with you when you go pick up the replacement. That J might designate a modified 48 frame. What projector is this off of? BTW: todays motors are generaly crap,alot of them made in China or overseas Asia. You may want to consider re-winding that motor if there is a good shop in your area.... especially if it is a modified frame.

Mark

Posted by Brad Allen (Member # 470) on 05-22-2005, 10:54 PM:

Its off of a Simplex 35. It's a Howell Motor. Original I'm guessing.

Posted by Michael Schaffer (Member # 1204) on 05-23-2005, 06:41 AM:

I have come across the code J48 also with Leeson motors where they are cross-referenced as NEMA 48 type N.
Problem with replacement motors for the Simplex is that the shaft size is non-standard (I think it is 5/8", but I am not sure if I remember that correctly off the top of my head). The motors currently supplied by Ballantyne are made by Leeson and have that modified shaft diameter and are AFAIK not available from other vendors.

Posted by Mark Gulbrandsen (Member # 72) on 05-23-2005, 07:10 AM:

Michael is correct. If that Howell Motor is a 1725 rpm model then you will more than likely have to have it rewound by a motor shop. The only other option is to convert the whole thing, pulleys and belts to sync type and install the new Leeson motor. At a cost of around 800.00+.

Mark

Posted by Brad Allen (Member # 470) on 05-26-2005, 02:55 PM:

Grainger to the rescue. A frame 48 motor fit just fine. I even found a perm lubed one with ball bearings.

The only concern I have is the VERY rapid speed that it brings the projector up to speed vs the old motor.

It's a cap start motor, is there a way to possibly change the starting cap to slow down the ramp up speed of the motor slightly?

This is the one I used Frame 48

Thanks all.

Posted by Gordon McLeod (Member # 33) on 05-26-2005, 03:17 PM:

Put a 1.5 ohm 300 watt resistor in line with it

Posted by Mark Gulbrandsen (Member # 72) on 05-26-2005, 04:19 PM:

Generally a smaller strarting cap will give less starting tourque. Same effect as Gord's resistor.

Mark