8mm Forum: Eumig Mark DL - motor stalled......

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Posted by Richard Gordon (Member # 1838) on December 09, 2009, 08:51 PM:

The motor of my Eumig Mark DL has stalled completely. I can rotate the spindle by prodding it so I assume the bearings have not seized. I can hear a hum...is it a funeral march or can the motor be saved? Grateful for your advice, Richard

Posted by Michael Dixon (Member # 1836) on December 10, 2009, 07:13 AM:

Not familiar with that machine. Will the motor run if spun by hand while energized? Single-phase electric motors must have some means of starting the motor, often by an auxiliary winding or by a "shaded pole". An Internet search should show photos of the shaded pole type. I just looked at one of the cheaper GAF projectors and it is shaded pole. Worn motor bearings/bushings may cause binding when the motor is energized as the windings pull the rotor tight against the field pole frames. Sometimes such wear is not evident if the motor is not energized. Shaded pole motors have very low starting torque. High drag/friction in other parts of the projector may hinder motor starting. If not shaded pole, look for a capacitor with the leads to the motor. If a capacitor is present, replace it and see if that solves the problem.
http://en.wikipedia.org/wiki/Shaded-pole_motor

Posted by Martin Jones (Member # 1163) on December 10, 2009, 07:32 AM:

Eumigs tended to use "shaded pole" motors (look for the copper shaded pole coils). Is the hum coming from the motor or the transformer? If from the motor, it sounds as if there may be shorting turns on the winding (usually a singe winding) If so, it's had it.
If you can send me a picture of the motor in situ in the machine to blagdonian(at)btinternet(dot)com I may be able to help further.

Martin

Posted by Richard Gordon (Member # 1838) on December 10, 2009, 05:45 PM:

Hi Martin and Michael, thanks for your replies. I've examined the motor; it's a shaded pole type (no capacitor and I can see part of the shading coil). The hum is from the motor! However, the spindle, though rotatable by using a screwdriver to push it round is quite stiff. So it's probable that the bearings need some lubrication. Is it possible to achieve this just by letting some light machine oil soak down the sides of the rotor?
Regards, Richard
Since writing the above, I've lubricated the rotor area and the top bearing; prodded the rotor round a bit "et voila!" - there's life after death [Smile]

. It's currently rotating as sweet as ever! Maybe I shouldn't have left it unused for 17 years....

[ December 10, 2009, 07:24 PM: Message edited by: Richard Gordon ]

Posted by Dino Everette (Member # 1378) on December 18, 2009, 12:20 AM:

Richard could you post a pic of the spots where you "oiled" it?

Posted by Martin Jones (Member # 1163) on December 18, 2009, 03:45 AM:

Only two points benefit from oiling..... the two shaft bearings.
The rotor runs with an air gap; no friction involved so oiling here only makes the rotor oily and it will eventually finish up in the bottom of the machine! My earlier remark about "had it" was based on "I assume the bearings have not seized".
Martin

Posted by Richard Gordon (Member # 1838) on December 21, 2009, 07:26 PM:

Hi Martin, yes I know there's an air gap; I trickled a little oil down the rotor because I could find no other way to lubricate the lower bearing without taking the projector apart!
Dino - I'll post a photo as soon as I can. Regards, Richard

Posted by Jeffrey Butler (Member # 6278) on February 01, 2018, 03:58 PM:

I have replaced my two belts on my Elmo ST 180 other than the red light coming on you would not know it was on.I can move the belts by hand, when I removed the old belts I am almost certain the motor was humming

[ February 01, 2018, 07:46 PM: Message edited by: Jeffrey Butler ]

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