Film-Tech Forum ARCHIVE: How "Hot" Should A Projector Motor Get?

This is topic How "Hot" Should A Projector Motor Get? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Don Furr (Member # 1469) on 07-02-2011, 09:47 PM:

I just finished running a 140 minute feature and the motor is too hot to hold you hand on it. As long as I've been running projectors I've never paid any attention to how hot the motor got.
How about some motor "heat" guidelines here.

Thanks...
Don

Posted by Bernie Anderson Jr (Member # 410) on 07-02-2011, 10:05 PM:

What's the projector set up?

Posted by Monte L Fullmer (Member # 2797) on 07-02-2011, 10:11 PM:

...could have a bearing starting to get hung up a bit...they should be warm to the touch..

Posted by Don Furr (Member # 1469) on 07-02-2011, 10:38 PM:

This is a Century JJ and a R3 sound head. I think I'll take the drive belt off and just let it run with no load. That should tell me if it's the bearings or a bind in the pulley/belt/sound head drive train. However it does turn very easy when I'm setting the shutter to thread.

Don

Posted by Randy Stankey (Member # 64) on 07-02-2011, 11:08 PM:

Isn't the maximum temperature of a motor supposed to be 25ºC above ambient or something like that?

Posted by Sean Weitzel (Member # 244) on 07-02-2011, 11:26 PM:

The motor driving my JJ-3 gets hot to the touch after a feature. I probably have personally put 1800 hours on the machine since I got it and suffered no ill effects.

Posted by Monte L Fullmer (Member # 2797) on 07-03-2011, 12:18 AM:

Okey ... maybe working a bit more pulling that wider gauge film through the machine.

what about 35mm operations - gets hot as well?

Posted by Frank Cox (Member # 6258) on 07-03-2011, 12:20 AM:

A few years ago I walked into my projection room toward the end of the show and the soundhead motor was on fire. (The first clue was the fact that the room was full of smoke.)

I'd say that was a bit too hot...

The timing was not too bad, though, as it was just at the changeover to cyan dye soundtracks, so I got a new soundhead while I was at it.

Posted by Lindsay Morris (Member # 1430) on 07-03-2011, 02:53 AM:

I have often wondered about my Century CC drive motor temp but after looking at the nameplate on it there clearly to see is 40C temp.
During the summer season on some quite hot nights in a NON airconditioned bio box the motor is almost too hot to touch at the end of the show. But given that the ambient in the bio is probably around 30C I guess a bit more than that is well and truly normal.
Never any smell of really hot windings and it is still going well after 5 quite hot summers.

Posted by Richard May (Member # 2627) on 07-03-2011, 09:05 AM:

I have a simplex with the same problem. It is very hot after each show. Been that way for 15 years and no issues.

Posted by Frank Cox (Member # 6258) on 07-03-2011, 12:50 PM:

Richard: Is your Simplex soundhead a direct drive or a belt drive? My soundhead that burned up was a Simplex direct drive and it always ran hot. The replacement was a Simplex belt drive and it never ran as hot as the direct drive did.

Posted by Don Furr (Member # 1469) on 07-03-2011, 03:35 PM:

As promised I removed the drive belt and began running the motor with no load 40 minutes ago. The motor housing is already heating up. I would suspect the insulation on the windings is breaking down allowing additional heat to escape to the motor housing. This is a vintage motor. I'll check it again after an hour but I'm betting is just gonna get hotter!
I'll post the results in a bit.

Don

***UPDATE***
After 1 hour 10 minutes the motor was red hot again. To the warehouse tomorrow for another motor!!!

Posted by Tony Bandiera Jr (Member # 2365) on 07-03-2011, 03:55 PM:

Ok, here's the skinny on motors:

A motor rated 40deg. C means that in can safely get as hot as 40 deg C ABOVE the ambient temperature of it's surroundings (within limits.)

A motor can operate safely at temperatures too hot to hold your hand on.

If there are no other problems, like excessive current draw, humming louder than normal or buzzing, smell of hot insulation/burning, or visible smoke or flames, then there is no need to worry.

If you are really concerned get one of those IR thermometers (or use a regular one taped to the motor shell) and get ACTUAL temperature readings. Anything below 195-200 degrees F is safe.

When in doubt, the best indicator is to throw an ammeter on the motor and check the current draw against the nameplate.

Posted by Louis Bornwasser (Member # 3063) on 07-03-2011, 06:10 PM:

btw: some motors will destroy themselves if run for long with no load. Louis

Posted by Richard May (Member # 2627) on 07-03-2011, 06:56 PM:

Frank, it's a belt drive with 5 star soundhead.

Posted by Mark Gulbrandsen (Member # 72) on 07-03-2011, 07:22 PM:

You're fine as long as it doesn't start on fire [evil]

.

Really, if it's an old motor blow the dam thing out with 30 pounds of air pressure. It'll probably release 35 years worth of dust and debris. Be sure to wear safety glasses and aim the output end of the motor away from your self and any valualable films sitting around.

Also, be sure the wiring to the motor is large enough. If you starve a motor by using too small of feed wire it will be running on low AC voltage and probably higher current and it may get considerably warmer than if it were wired correctly... with #12 stranded THHN wire. I had one city that required them to be wired with #8 THHN! That inspector was really lost in his guidelines.

On Christie P-35 motors or Simplex X-L with Bodine motors occasionally remove the end cover thats over the fan blade on the end of the motor shaft. The metal fins on these motors generally become completely plugged with lint and fuzz over a several year period. Lots of Simplex Bodine motors have failed because of this... The Christies have a thermal breaker in them that will open till the motor cools down... this occurs well your cue to do the cleaning.

Oh, and Don... Shouldn't you be thinking of converting to digital anyway and retiring that quaint old equipment??? [Wink]

Mark

Posted by Don Furr (Member # 1469) on 07-03-2011, 08:02 PM:

Ha Ha...NO Mark. I'll never retire my JJ!! Most of what I have isn't on Digital. I don't "do" the new stuff. [Big Grin]

Don

Posted by Frank Cox (Member # 6258) on 07-03-2011, 09:50 PM:

quote: Mark Gulbrandsen
You're fine as long as it doesn't start on fire

Now he tells me...

Posted by Mark Gulbrandsen (Member # 72) on 07-04-2011, 09:29 AM:

I just yanked a JJ... Very low S/N. Two JJ are staying in this complex for kiddie shows...

Posted by Monte L Fullmer (Member # 2797) on 07-04-2011, 12:11 PM:

When I used to work for a company that ran STRONGS and Bodines and their equipment wasn't in the best of clean areas, every 6 months, I would take the rear cover off those Bodines and brush out the junk that would collect under those covers since the air actually flows between the fins of the motor and that's where the junk would love to collect the most was the entrances to the fins under the covers.

Now, wonder if they'r getting clean now, but it's not my problem.

(..now, I have Barco filters that I have to keep clean once a month... and still some Bodines that spins P35 units).

-Monte