Film-Tech Forum ARCHIVE: Question on Eprad Mutts

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Posted by Sam Hunter (Member # 1119) on 08-29-2003, 06:27 PM:

Can any body tell me the type and ratings of the servo motors used on EPRAD DBL Muts? Need Max Voltage, MAX RPM, Motor manufacturer, etc.
Thanks!

Posted by Gordon McLeod (Member # 33) on 08-29-2003, 06:56 PM:

Most were 115vdc General Electric Boston Gear motors

Posted by Bruce Hansen (Member # 281) on 08-30-2003, 09:11 AM:

I have eprad wall mutts, as Gordon said they are GE 115VDC motors. There is also a label on them that says Paterson Gearmotor, 345 RPM, 21 in-lb torque, 1.2 Amps, class B-R, 115VDC, permanent magnet, Motor model 5BPA34LAB3D, Gear model GS112DX3UY12A01. Hope this helps.

Posted by Sam Hunter (Member # 1119) on 08-30-2003, 09:21 AM:

Helps a great deal!
Thanks!

P.S. Wouldn't know where I could find a couple cheap would you?

Posted by Mark Gulbrandsen (Member # 72) on 08-30-2003, 11:36 AM:

Sam,
Do a search of surplus places on the net such as Surplus sales in Omaha. You are bound to find something. I like the Double Mut alot and it works great. Building one would not be difficult and if you need and dimensions or schematics let me know. Be sure to includ the 300 watt light bulbs to dampen things out. It'll run without them but not as smooth.

Did any of you know that the Double MUT was originally designed for 3 strip Cinerama????
Mark @ CLACO

Posted by Sam Hunter (Member # 1119) on 08-30-2003, 12:07 PM:

I have built my version of the DBL MUT and I am using 2 150RPM fitness machine motors and it seems like it will work ok but the motors are a little noisy for my liking. I still need some 3" film guide rollers and keepers to finish this project and I am finding them hard to find at least in a price that I can afford.
Here are some photos of the HunterLabs Spool system.

Thanks.

Posted by Dave Ganoe (Member # 53) on 08-30-2003, 12:40 PM:

Mark,
Do you have those dimensions and sch. in electronic format? If so would you email them to me. Id like to build one for myself. I have a platter but dont have room in my new place to use it so Id like something smaller and more compact. THanks.
Dave

Posted by Bruce Hansen (Member # 281) on 08-30-2003, 04:05 PM:

There is a manual for the double mutts in the manuals section right here on film-tech. The wall mutts are pretty much the same thing, just mounted differently. By the way, the manual talks about the lamps that are right accross the motors, but does not show them in the diagrams.

Posted by Ron Yost (Member # 1850) on 08-30-2003, 07:38 PM:

Sam, you're a wonder! Love folks that can make something out of not much .. came from my dear old Grandpa. He had to do that his whole life and never once complained.

Resourcefullness .. a lost art in America.

Ron Yost

Posted by Tim Reed (Member # 137) on 08-30-2003, 08:48 PM:

Sam, is there nothing you can't build? I'm impressed!

Posted by Warren Smyth (Member # 1838) on 08-31-2003, 01:01 AM:

On the subject of drives for home made mutts my experience maybe of value to someone. I built a system using the take up motor and combined gear reduction and spindle unit from a scrapped Cinemecannica Vic 10. This is simply bolted through an mdf plate which is mounted verticly on a solid base. The half inch spindle protrudes through a 56mm hole to the other side. The motor and take up assembly is held in place by the clamping ring which is mounted on the reverse side to that of the motor. This clamping ring is part of the original assembly. The mounting is therefore the same as that used originally to mount the assembly to the lower projector magazine plate.

I have mounted a sprung roller arm which drops to take up the slack momentarily, at the start. This, then very gradually, lowers again during the filling of a 10,000 ft reel. There is no speed nor torque control. The slipping clutch handles the load admirably and with the jockey roller arm , an even tensioned wind is accomplished.

The feed is simply from the feed clutch, spindle and support arm from the same machine with the magazine removed. This is mounted against the reverse side of the mounting plate to that of the take-up motor and acts as a bracket support for the plate. The base of the magazine support arm had to be raised 40mm to allow clearance for 10,000ft reels. The feed spindle is 400mm from the base and the take up spindle is 900mm from the base, each spindle pointing in opposite directions.

It works a treat and is very compact. The only complication, is that the motor require 3 phase supply and reels with half inch bores are required. There is no strain at any time on the film. I use a Kalee sound head which has a sprung roller before the take-up to remove any irregularities. This spring assembly is not under any load at all, in fact it runs smoother than it does feeding 2000 ft reels on it's own take-up spindle.

If you have access to a scrapped Vic 10, there is very little extra cost involved. It's an ideal project for someone that hasn't got an engineering workshop and doesn't want to re-invent the wheel. The motor was designed to take 5,000 ft of 70mm film and it handles 10,000 ft of 35mm film very well. I suggest that the distance between projector and the device be as short as practicable.

At present I wind the film back by hand but the recent gift of another Vic 10 take-up motor unit is going to change that.

Posted by Paul Trimboli (Member # 1509) on 08-31-2003, 03:01 AM:

Very impressive setup! I had been thinking about building a system that is like a 2 deck platter and the films pays out from the edge and requires rewinding, like the IMAX MK1 platter system. My main concern was how to use the variacs for takeup and payout tension, how long a dancer arm would I need? The Eprad DBL MUTT had chain driven variacs off the dancer arms, so what size gears would I need and where would I but them from? At the moment at work we have an ORC platter thats has variac driven take up, just a normal of the shelf one with the knob removed!

Posted by Matthew Bailey (Member # 601) on 08-31-2003, 04:59 AM:

I would make a double MUT or spool tower from a Kelmar rewind motor & control unit fitted with a double v pulley & a pair of combo reel/guidance arms that have the take-up pulley on them.

Posted by Kevin Wale (Member # 1851) on 08-31-2003, 06:13 PM:

MAN THAT IS COOL! [Smile]

I really liked the double mutts we used to have in the other theatre. They were old and getting worn out, but I really liked the concept. They had all metal rollers which I didn't like but that is a chagable thing.

Does your speed knob allow to change direction with just the knob making it possible to rewind or play from either side?

Excellent work... just great. [Smile]

Posted by Sam Hunter (Member # 1119) on 09-01-2003, 05:37 PM:

Well, first off thanks for the compliments [thumbsup]

To answer some of your questions:

I have to say that I am still needing 6- 3" film guidance rollers to finish this monster. I would have thought those things would be all over the place but apparently not.

Anyway, on the dancer arms, I am using a 4:1 gear ratio as the arms will travel about 90 degrees and I am needing full rotation of the 20K Pot. I have 3:1 right now as I miscalculated so I had to order new gears [Frown]

.

The speed control on rewind is one way only. I know it would be beneficial to have it reversable but it will have to wait for a later revision so in the meantime I will just have to watch out for the yellow tape [Big Grin]

.

I have yet to actually run this contraption with my projector (see above roller statement) and I am worried about everything working right and not having a major disaster happen. My hope is that it will work right the first time [Eek!]

Anyway, I will post a progress report if anybody is interested.

Later.

Posted by Ron Yost (Member # 1850) on 09-01-2003, 07:19 PM:

These are the times ya' need a print you don't care about, huh Sam. Where are all those Gigli, Justin & Kelly, etc., prints we could use for such purposes?? Largely gone to the bandsaw by now, I guess. [Big Grin]

Ron

Posted by Sam Hunter (Member # 1119) on 09-01-2003, 07:26 PM:

I wouldn't insult my little BX with that crap [Big Grin]

I have an acetate stock movie that can be sacrificed.
You need to post a pic Ron so I can see who my newest buddy is [Wink]

Posted by Paul Trimboli (Member # 1509) on 09-02-2003, 08:14 AM:

Will a pot be up to the job for the dancer arms? I had thought of using a pot but thought the physical load would be to much in terms of wear?

Posted by Sam Hunter (Member # 1119) on 09-02-2003, 08:37 AM:

The dancer arm in my setup is connected through a shaft which connects to a 4" Delrin Spur gear, this gear meshes with a .75" spur gear connected to the pot.

The pot is under no load at all and I also have added stops to the dancer arms to keep them from going past a certain range of motion.

The two photos show the gears and how they are situated and the other shows the dancer arm and the stops to limit their motion to keep from twisting the pot apart. Keep in mind that the arms will have a range of about 90 degrees and this range will need to turn the pot to its full travel thus the 4:1 ratio.

Posted by Paul Trimboli (Member # 1509) on 09-02-2003, 08:50 AM:

Very interesting! I look foward to hearing how you go. This would make for a much cheaper setup then using 2 variacs. The ones I have found in Australia are $200 each so not cheap.

Posted by Sam Hunter (Member # 1119) on 09-02-2003, 08:58 AM:

Hey,
Check ebay for VARIACS. I found some New in boxes for 10 bucks a few weeks ago. I bet you can find something good like that. What I didn't state is that I am using PWM servo motor supplies at which I bought from an Surplus company. While they are effient and designed to work with the motors I am using they have a slow ramp speed and have to be started in the slow speed.
I might have used VARIACS bought we will see.
later.

Posted by Sam Hunter (Member # 1119) on 09-16-2003, 07:15 PM:

Finally finished this damn thing. Man, for the money I spent building it I could have bought a DBL MUT. I would have too if I would have had room for it.
Anyway, it works great and really surprised me in its smoothness. Had a couple of bugs to work out but I managed to beat it into submission.