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Bolex WM vs MM takeup motors


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#1 Robert Ditto

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Posted 14 June 2011 - 10:12 AM

Hello all!

Can someone tell me the differences between the WM and MM take up motors for.the Bolex 400ft Mags and which would be better to use?
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#2 Jean-Louis Seguin

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Posted 14 June 2011 - 01:28 PM

Hello all!

Can someone tell me the differences between the WM and MM take up motors for.the Bolex 400ft Mags and which would be better to use?




The MM motor is the earlier design and was designed to be used with the MST motor which ran only at 24fps or 25fps.

When used on the EBM Electric or with the ESM motors at 50fps, it can be a bit sluggish.

The WM motor was introduced to supplement the newer H16 EL cameras which has a whole range of speeds.
It has 4 different torque settings: 10-12fps, 18-25fps+Sync, 32-40fps, 50fps.

A lot of older MM motors have developed over time a annoying squealing noise that is often impossible to eliminate.

They both run off the same 12VDC supply as the camera but the power input connections are different on the MM and the WM.

Cheers,
Jean-Louis
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#3 Chris Elardo

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Posted 14 June 2011 - 01:34 PM

The MM motor is a constant speed motor made to take up film while the camera is running the standard 24 fps. The problem is that you must be careful when shooting for slow motion, or fast motion since the MM motor is not adjustable to compensate for film being run through the gate at faster/slower rates (filling the camera chamber with film or over tensioning the film exiting the lower sprocket).

The WM motor, however, is designed specifically to address this problem. It has a speed adjustment knob that can be used to match the speed of the main motor so that film is being taken up into the 400' magazine at the same rate as it's being fed through the gate. The WM motor is definitely harder to find and much more expensive than the standard, common MM motor.

Hope this helps-
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#4 Robert Ditto

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Posted 14 June 2011 - 03:00 PM

Hey thanks guys!

Is there an adapter for the EBM or will I need to do some custom working to use the WM motor?
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#5 Jean-Louis Seguin

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Posted 14 June 2011 - 03:22 PM

Hey thanks guys!

Is there an adapter for the EBM or will I need to do some custom working to use the WM motor?




There are no off-the-shelf adapters that I know of.

A custom adapter could be made or else modify the motor cable or the camera.

Cheers,
Jean-Louis
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#6 Chris Millar

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Posted 14 June 2011 - 04:53 PM

A lot of older MM motors have developed over time a annoying squealing noise that is often impossible to eliminate.

Cheers,
Jean-Louis

Yeh!

What is that damn noise ? I have three, one does it - one is for parts and I've opened it up on occasion but I'm not too keen on doing it on the noisy one - they're not made for easy access huh

It cant be impossible though right ?? Its just well, stuff and stuff can be made to do and not do things right ?

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#7 Jean-Louis Seguin

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Posted 14 June 2011 - 08:53 PM

Yeh!

What is that damn noise ? I have three, one does it - one is for parts and I've opened it up on occasion but I'm not too keen on doing it on the noisy one - they're not made for easy access huh

It cant be impossible though right ?? Its just well, stuff and stuff can be made to do and not do things right ?




Hi Chris,

As you know, inside the MM, there are two miniature Maxon gearhead motors. I've tried a number of times to apply fine oil in strategic areas of the motor shaft and gear-train inside the motor itself and sometimes it would seem to work then after a while the noise came back and sometimes the noise could not be eliminated at all. As an experiment, I once dunked the whole motor in an ultrasonic cleaner. The noise seemed to disappear for a while then returned. I think the noise is from inside the little motors themselves. If an identical new little motor could still be found at a reasonable price, I'd just replaced them with new ones but the cost would probably make it economical.

To be honest, I don't think there are a lot of people anymore using 400 foot mags on the Bolex, at least not amongst the people I deal with.

Cheers,
Jean-Louis

Edited by Jean-Louis Seguin, 14 June 2011 - 08:55 PM.

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#8 Chris Millar

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Posted 14 June 2011 - 09:11 PM

Hi Chris,

As you know, inside the MM, there are two miniature Maxon gearhead motors. I've tried a number of times to apply fine oil in strategic areas of the motor shaft and gear-train inside the motor itself and sometimes it would seem to work then after a while the noise came back and sometimes the noise could not be eliminated at all.

Yup,

My parts version is actually a worker, just that one of those motors no longer works - at slower speeds the single motor can keep up, especially if you give it a manual hand between takes... But potentially inside those things huh Posted Image the one that wasn't working had an aborted attempt at a fix but they are pretty solidly compacted units, the issue was in the commutation, and I was way too rough in my approach for that fiddly little set up in there... melted a hole in the clear plastic for access - oh dear ! The 'brushes' or maybe just what is left of them are just wire...



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#9 Jean-Louis Seguin

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Posted 15 June 2011 - 07:44 AM

Yup,

My parts version is actually a worker, just that one of those motors no longer works - at slower speeds the single motor can keep up, especially if you give it a manual hand between takes... But potentially inside those things huh Posted Image the one that wasn't working had an aborted attempt at a fix but they are pretty solidly compacted units, the issue was in the commutation, and I was way too rough in my approach for that fiddly little set up in there... melted a hole in the clear plastic for access - oh dear ! The 'brushes' or maybe just what is left of them are just wire...




Correction. I made a boo-boo.

The motors are probably not Maxon as they are manufactured in Germany as the complete MM unit is also.
Maxon is Swiss company and the motors inside the EBM and EL are Maxon.

Cheers,
Jean_louis
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#10 Carl Elsaesser

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Posted 26 August 2013 - 05:18 PM

When used on the EBM Electric or with the ESM motors at 50fps, it can be a bit sluggish.

 

 

Hey there Jean-Louis Seguin,

 

I'm just wondering what you mean when you say the mm motor is a bit sluggish when run at 50 fps. Is it still workable, or does it totally throw off the light reading and make the film jump around. I'm working on a shot that's gonna be about 3 minutes long and we were hoping to shoot it at 50 fps with the mm take up motor. It doesn't have to be sound synch but it would be nice it the light was exposed evenly across the shot. What do you think?

 

What about running the camera at 40fps.... you think that would make a difference? 

 

cheers,

 

carl 

 


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#11 Jean-Louis Seguin

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Posted 26 August 2013 - 07:36 PM

In your case, the best way to know for sure is to thread a full 400 foot of dummy film and run it through from beginning to end at 50fps with stops occasionally. You can run it with the doors off to see the whole process. Check the take-up reel if it's tightly wound.

Best case scenario: it will be a little loose.

Worst case: the film will fail to take up properly and pack up in the film chamber.

You may have to manually inch the take up reel snugly between each take to be sure.

It will in no way affect exposure but film that is loose in the chamber will be susceptible to scratching.

 

Jean-Louis


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#12 steve waschka

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Posted 31 August 2013 - 07:07 AM

squealing noise: is inside, inside, and then inside the little motor bearing areas. I fixed my last one over a year ago. I do remember that once you take the brush housing off the back and the gear train off the front of the little motor itself... the wound core is still inside more baffles that i dare not remove. Many many times i oiled further out on the assembly thinking " i got it this time".....nope. Finally just completely over it I packed the little motors front internal gearing with high quality clear machine grease. Just kept pushing it in. Noise never came back. Motor didnt blow up. If I remember correctly the noise was not fixed by anything I did in the back of the brush assembly  And once you break that seal you have to carefully readjust the timing of the brushes or the motors will fight eachother during use.


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#13 Chris Millar

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Posted 01 September 2013 - 01:58 AM

I know those brushes! If I recall that part took some partial destruction to get into and I never got it back again...  I had three motors (i.e. six little motors) so it was more out of interest - I got one working out of non-noisy parts, a really noisy one, and a dead one. Turns out one of six was actually missing. The motor had been running on just one all that time, no wonder it couldn't handle a full reel. Typical eBay seller for you 'one owner since purchasing', replied back saying he was not aware of any issues etc...  Yeh, right whatever ;)


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