Film-Tech Forum ARCHIVE: Bodine Sync motors overheating on occasion

This is topic Bodine Sync motors overheating on occasion in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Monte L Fullmer (Member # 2797) on 01-03-2010, 04:09 AM:

Hello again all.

Now, it's my turn for a little help.

Scenario: Bodine sync motors mounted on 5 star soundheads.

Got a note from one of the theatres that I service and they noticed that when they spin the flywheel to set the intermittent sprocket to lace up, that the flywheel is "hotter n'hell" when touched.

Yet, this is not a constant issue but just an rare to occasional issue.

The Simplex 35 has no drag on it-turns with no resistance. Trap and Gate tension is correct where there is no film drag resistance on the mechanism during operation.

Motor starts up with no hesitation - spins up normally knowing that the starter circuit inside is doing its thing.

These two motors, at the times when I'm there, have given me no problems in the past when I'm there to observe these operations.

Yet, they've had issues with fluctuating line voltage like almost a good 5 volt difference. Would this be the cause of this overheating? For, at one time, one motor got so hot that the thermal inside opened causing this one motor to die and I told them to let it cool down to allow the thermal to close to get back to normal operation.

When I worked with the P3GPS units by Christie, those Bodines would act up as well - overheat to where the thermal opens and we would have to let them cool down until the thermal closes.

Thx for any help on this one. "Dang", guess I'd better tell them to head to Leeson's if Bodines aren't the winning ticket.

thx -Monte

Posted by Ian Parfrey (Member # 5122) on 01-03-2010, 05:01 AM:

Monte.

I'm not overly familiar with the Bodines, but is it possible the starter circuit is not being switched out after full speed is reached?

Do these motors have mechanical starter switching or electronic?

Posted by Louis Bornwasser (Member # 3063) on 01-03-2010, 08:44 AM:

Monte; have them run the motor for several hours before you get there. (Open the gate, no film) See if you feel the heat after that time. If you do, yoiu may have a bearing that grabs only when hot. Louis

Posted by Shaun Flichel (Member # 1435) on 01-03-2010, 01:33 PM:

We used to have a solid pipe to wack the motor on the back. I think its the start winding sticking.

Posted by Phil Hill (Member # 371) on 01-03-2010, 01:41 PM:

quote: Monte L Fullmer
...sync motors...

So Monte, which is it...A sync motor or an induction motor with a centrifugal start switch and start winding?

Most sync motors have a start capacitor and a run capacitor and no centrifugal start switch.

If the start winding of an induction motor didn't release, it would burn up.

If a sync motor, I would suspect a faulty capacitor.

Posted by Randy Stankey (Member # 64) on 01-03-2010, 01:52 PM:

Aah! It's those old "Jethro Bodine" motors!

I've seen about a half dozen of those just overheat and die for no apparent reason. Switched them with a brand new Leeson motors and never had a lick of trouble with them again.

Posted by Mark Gulbrandsen (Member # 72) on 01-03-2010, 03:07 PM:

Actually buddy... take the cover off the fan end of the motor and you'll prbbly find that end of the fins completely clogged with dirt. Once they are clogged it prevents proper cooling of the motor and it'll eventually burn up...

This problem also exists on Christie projectors which use a similar Bodine motor...

Mark

Posted by Monte L Fullmer (Member # 2797) on 01-03-2010, 03:49 PM:

Hi Phil - they're syncs since they have the two caps -the start and run caps - attached to the frame.

Yo, Mark - not a cooling issue since I've already blown out the rear ends of these things, but do agree with Randy's statement about seeing Bodines go without any reason, for this location already has three Leesons attached, which are tonnage better motors than Bodines in the long run.

Do have some spare Bodines to do a swapout, but just wondered why this sudden heatup situation.

Thx all for the help - Monte

Posted by Phil Hill (Member # 371) on 01-03-2010, 04:13 PM:

Thanks Monte for clearing that up since many comments in this thread related to induction-type motors...

Posted by Gordon McLeod (Member # 33) on 01-03-2010, 05:22 PM:

the bodines have had issues but then so have most sync motors

Posted by Monte L Fullmer (Member # 2797) on 01-03-2010, 06:45 PM:

K, got back from doing that swapout with another Bodine and got them on their merry way even though the original one wasn't getting hot or experiencing any problems ..

(sorry on the misconstrue about starting circuits, but I thought I was hearing a startup circuit swinging one over, but that's was coming from a LEESON motor and don't know the circuitry too well when it comes to sync motors)

, but have to ask: on how to check for bad caps if the possibility of having either a bad start or run cap could have caused this heating issue (or, as what Louis said on bearings are grabbing on occasion) so I can keep my butt covered next time since the office uppers gets all panicky when stuff like this happens and turn the fire up full blast underneath me for me to cure the issue?

thx-Monte

Posted by Michael Voiland (Member # 5386) on 01-03-2010, 09:07 PM:

These motors are hot things. We have 4 of them mounted on top of pro 35 projectors. One is currently dieing. When I go in in the morning and the thing is cold the start winding sticks on and the whole thing vibrates until it works its way loose. Then its fine for the rest of the day. The vents for the bodine motors are those fins that run under the cover for the fan blade. They get plugged up with large clumps of dust. Take an air compressor with a basket ball filling fitting at 80 psi or so and blast the dirt out.
The still run very hot.

Posted by Jake Spell (Member # 5294) on 01-03-2010, 11:04 PM:

best way to check the cap is to buy a meter that reads micro farads, both fluke and fieldpiece make them, and I know supco make a meter that only reads micro farads.

Posted by Monte L Fullmer (Member # 2797) on 01-03-2010, 11:36 PM:

quote: Michael Voiland
The vents for the bodine motors are those fins that run under the cover for the fan blade.

Thx..I usually take the end cover off and do the brush method to rid of the dust stuck inbetween the fins on the frame...

-Monte

Posted by Monte L Fullmer (Member # 2797) on 01-04-2010, 01:00 AM:

(missed the time limit to edit previous post)

Would multiple (three second) bump starts per a period of time cause the start caps to begin failing? If so, would I need to enlarge the rating on the caps or add a bleed resistor and if so, what size? Wonder if this is the beginning of this whole fiasco..

Now, the big huge question is so I can put this topic with my uppers to bed so I can be left alone over this: I do the cap check and they're okey. I run a bench test on these things with hooking up a cheater cord to the inlet wires and let it run by itself .. and it doesn't heat up .. what do I tell them?

Yank out all the Bodines and put in LEESON's would be the obvious answer...but....that's an illogical solution right now.

Thx again for all the help for me on this topic...

-Monte

Posted by Dave Macaulay (Member # 813) on 01-04-2010, 02:02 PM:

The motor is very simple. The rotor is just a complicated lump of metal. There are a few coils in the stator, relatively foolproof but occasionally windings short together because of poor or abraded insulation (it's just a paint-like coating). The two bearings are easily replaced and are inexpensive standard types. The two capacitors are prone to aging badly, but are cheap to replace as well. The motor will overheat when run with out-of-spec capacitors - although they run pretty hot even when all is perfect.
The caps will be available at any motor repair shop. You can have the shop change them for $$$ (probably replace the bearings and blow dust out as well) or do it yourself for much less. Just mark the wires so you get them on the right lugs. Much smoke and distress can result from mixing these up!

Posted by Louis Bornwasser (Member # 3063) on 01-04-2010, 05:49 PM:

Swap capacitors with a known good motor and follow the trouble/ Louis

Posted by John Hawkinson (Member # 1135) on 01-04-2010, 07:49 PM:

I'm not really up on motor caps, but caps can fail in ways other than changing their capacitance. Their equivalent-series-resistance can change (increase). I guess that's about it. They can short or go open, but you'd find that with your cap meter.

--jhawk

Posted by Monte L Fullmer (Member # 2797) on 01-05-2010, 01:32 AM:

I remember (slightly) on how to check caps with a VOM:

1-discharge the cap
2-set the rating to Ohms x 100k
3-If resistance falls to zero then arises, cap is normal
4-If resistance stays at zero, cap is shorted out
5-If resistance remains high, unit has opened up.

Please correct me if this is incorrect .. thx-Monte

Posted by Mark Gulbrandsen (Member # 72) on 01-05-2010, 08:21 AM:

Thats correct for those tests Monte but that isn't going to show you if the capacitor has changed value which in your case may be the more likely problem. Many digital meters have at least a simple capacitance checker built into them now...

Mark