8mm Forum: Speed variation: Eiki SSL runs a hair fast.

This is topic Speed variation: Eiki SSL runs a hair fast. in forum 16mm Forum at 8mm Forum.

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Posted by John A. Pommon (Member # 292) on November 03, 2005, 08:01 PM:

I have an Eiki SSL-O/3580 that
runs just a tad over speed. The pitch of familiar voices is slightly higher. I could try swapping out the motor module and transformer module with another machine to isolate the problem. Ever had this problem on an SSL?

[ November 04, 2005, 01:03 AM: Message edited by: John A. Pommon ]

Posted by John Whittle (Member # 22) on November 04, 2005, 09:25 AM:

John

Rather than swaping modules, have you just tried the pulleys? Never seen this with the flat belt models but it was common on the older round belt models when the wrong belt was used and it didn't ride in the grove to the proper depth.

Did this just happen or is it a "new" machine? If it's new to you, I'd suspect the pulley parts, if it just happened, then your guess about the motor is probably correct although they usually loose torque and start running slow especially under load of a full 2000 foot take up reel towards the end of a show.

John

Posted by John A. Pommon (Member # 292) on November 04, 2005, 04:51 PM:

Hi John, thanks for the tip on the pulleys. Both the main drive belt and the shutter pulley belt look good. They are the flat belt styles. I'm getting 125V at the wall outlet. I guess I'll try swapping out the power tranny first.

Hey John is there a way to measure the speed of the machine? I suppose I could see how much time it takes to run 100' of film and compare with a known good machine.

Posted by John Whittle (Member # 22) on November 04, 2005, 09:53 PM:

quote:
I guess I'll try swapping out the power tranny first

The motor is wired directly to the line, it has nothing to do with the transformer. Fast is really unusual unless the belt is riding high and not in the groves.

What I do to check (not having a digital tach) is take 36 feet of film (leader) put an "X" on one frame with lines to and from to warn me it's coming up and splice it into a loop. Then show the film and start a stop watch on the first "X" flash and let and run five times (180 net feet) and stop the watch and see how close it is to five minutes. The error will compute to your frames to second.

It's crude, but it's cheap and it does the job.

I must say, I've never run across a "fast" machine unless the pulleys were wrong (on the 50 hz instead of the 60 hz) or the belt was riding up and not in the "V" groves. Remember it's an induction motor so the speed is not voltage dependent but frequency dependent (withing reason of course).

John

Posted by John A. Pommon (Member # 292) on November 05, 2005, 01:01 AM:

quote:
Fast is really unusual unless the belt is riding high and not in the groves.

Hi John:
That is the first thing I thought so I pulled the backs off of two machines. Indeed the belts are both in the groove.

Thanks for saving me time by not wasting it on useless transfer of power transformers to see if the problem transfers.

quote:
What I do to check (not having a digital tach) is take 36 feet of film (leader) put an "X" on one frame with lines to and from to warn me it's coming up and splice it into a loop. Then show the film and start a stop watch on the first "X" flash and let and run five times (180 net feet) and stop the watch and see how close it is to five minutes. The error will compute to your frames to second.

Thanks John.

I will clock 'em sometime this weekend.

I'm curious to compare the time it takes to run the 36'
on each machine.

Posted by John A. Pommon (Member # 292) on November 11, 2005, 11:18 PM:

Hi John:
The Eiki SSL in question ["hair" fast] clocked 4 minutes and 48 seconds to run 100' of film. I ran the same 100' roll on a known correct-speed Eiki SSL and it timed out at precisely 5 minutes (12 seconds more).

Mr. Whittle: I am stumped.

Posted by Jan Bister (Member # 332) on November 12, 2005, 09:06 AM:

I just did some quick calculation and you may be surprised to find that - based on the assumption that your good machine runs at exactly 24fps - the too-fast machine runs at exactly 25fps. Which sounds to me like someone modified that machine in some way to turn it into a telecine projector for PAL video capture. That could just be coincidence, though.
If I were you, the next thing I would do is actually comparing the motor spindles and shutter wheels in both projectors to see if they're the same size, or if something in the too-fast unit was enlarged/reduced in size to make it run faster.

Posted by John A. Pommon (Member # 292) on November 12, 2005, 03:39 PM:

Thanks Jan for the help. Both machines have two blade shutters installed [by me] years ago. Now that you mentioned the frame rate I wonder if the machine was made up of parts perhaps intended for another country.
The shutter assemblies and motor spindles appear to be the same.
I suppose I should get a caliper and start comparing.

[ November 14, 2005, 02:52 PM: Message edited by: John A. Pommon ]

Posted by John Whittle (Member # 22) on November 16, 2005, 09:17 AM:

quote:
Thanks Jan for the help. Both machines have two blade shutters installed [by me] years ago. Now that you mentioned the frame rate I wonder if the machine was made up of parts perhaps intended for another country.

Actually most of the projectors were shipped with 24/25 pulleys and shutter drive set-ups. The old sound/silent went away since the only way to change speed was to take the back off the machine. I think they still offered the 24/18 for 60hz countries but it would have been a special machine.

I'd be more interested in your speed check and see if one machine was actually running a little "slow" rather than one running fast. That would be more likely a problem with the motor or the physical load from the projector combined with a slight loss of torque as the motor ages.

John

Posted by John A. Pommon (Member # 292) on November 16, 2005, 02:10 PM:

quote:
see if one machine was actually running a little "slow" rather than one running fast.

Hi John, Thanks for the suggestion. After running a few prints through the "control" machine I am satisfied it runs within spec - the pitch sounds correct [the pitch of the voices normal].

The machine in question still runs 100' in 04:48 raises pitch slightly and is a 'mystery' how that can happen. [Confused]

Posted by Jan Bister (Member # 332) on November 16, 2005, 11:35 PM:

Hmm. It's not the belt, it's not the shutters, not the pulleys or motor spindles... everything appears to be 100% the same between the two machines... maybe your fast machine needs an exorcism... [Eek!]

Posted by John A. Pommon (Member # 292) on November 17, 2005, 03:34 AM:

Hey Jan, I need to take both machines apart side by side and hunt for a problem, start swapping parts 'till the problem transfers or maybe it won't . . . [Eek!]

[ November 17, 2005, 07:55 PM: Message edited by: John A. Pommon ]

Posted by Jan Bister (Member # 332) on November 18, 2005, 12:49 AM:

I was thinking about this today (for some reason) and figured "maybe some cog wheel or other has a different number of teeth in one machine than it does in the other, resulting in faster speed, and somehow this affects the sprockets transporting the film" ... which was until I realized that the sprockets have to run in sync with the claw, of course, or the film wouldn't last very long before having its perforation shredded to pieces. [Roll Eyes]

So the logical conclusion is that the problem must be in the shutter wheel (which drives the claw), or somewhere in the mechanical "pathway" before that (belt, motor, whatnot). At least that limits things somewhat...
I wonder, anyway, what kind of difference in pulley sizes etc. there would have to be to cause the speed difference between both projectors, and whether that size difference would be noticeable with the naked eye or not...

Posted by John Whittle (Member # 22) on November 24, 2005, 05:52 PM:

quote:
The machine in question still runs 100' in 04:48 raises pitch slightly and is a 'mystery' how that can happen.

Well, that's a "mystery". 16mm film at 24 frames per second runs 36 feet per minute (40 frames to the foot) so 3 x 36 is 108 feet in three minutes. 4:48 would be r-e-a-l-l-y s-l-o-w.

So maybe it was 2:48? At that rate it's almost perfectly on speed (168 seconds times 24 frames per seond equals 4032 frames or 100 feet plus 32 frames or almost 101 feet).

That would mean the other projector is running a bit slow. Watch a few PAL tapes and your ears will adjust [Smile]

What's the speed of the "slow" machine for a 100 feet versus the "fast" machine?

AS far as I know, these are the only things that will affect speed:

1. Shutter pulley (wrong or defective--i.e. 'fixed' by someone)
2. Motor pulley (wrong or on wrong size)
3. Motor (although it would most probably be slow not fast--induction motors respond to hz more than voltage hence the same motor on 50 hz runs slower than on 60hz and the reason for the two steps on the motor/shutter pulley)
4. Physical load of projector (again sould cause it to slow down not run fast).

Thus if the projector is running fast, then it might be a defective motor pulley (start there first). Or a defective motor belt that is riding "high" on the pulleys (I've actually seen that happen with an Elmo).

John

John

[ November 26, 2005, 04:08 PM: Message edited by: John Whittle ]

Posted by John A. Pommon (Member # 292) on November 27, 2005, 10:43 PM:

Pardon me John . . .
Re-stated correctly, after measuring five minutes of black 16mm leader [using a Moviola counter that measures in hrs/mins/secs] I ran the five minute roll on the Eiki SSL machine in question and it took only 4 mins. 48 secs.

On the "control" machine the same roll runs precisely five minutes.
[same 120VAC supplies both machines]

The belt looks in the groove. . . . same as the other machine. I've seen a belt run atop too (but I forget what it was on) [Eek!]

it's been a while. Both machines look identical in every way.

John, I guess the only thing to do now is to transfer motors between machines to see if the problem transfers. [Confused]

[ November 28, 2005, 03:30 AM: Message edited by: John A. Pommon ]

Posted by John Whittle (Member # 22) on November 28, 2005, 07:19 PM:

quote:
John, I guess the only thing to do now is to transfer motors between machines to see if the problem transfers.

Having been in that battle myself (with round belts that rode at a different level on earlier machines), I'd suggest you start with the motor pulley (less stuff to move and connect!) and see if you get a change in any direction. It could be someone put a pulley on from another machine (like a 24/18 from a 50 hz machine) or heaven only knows what. That's part of the fun, you never know what you'll find when you open these things up with so many "do-if-yourselfers" that don't have the books.

John

Posted by John A. Pommon (Member # 292) on November 29, 2005, 07:38 AM:

John, eyeballing both machines the motor pulleys attached to the motor modules of both machines look to be the same diameters. Rats . . .where's a caliper when you need one. How close is a 24/18 in appearance?

Posted by John Whittle (Member # 22) on November 29, 2005, 02:13 PM:

quote:
where's a caliper when you need one. How close is a 24/18 in appearance?

Pretty damn close! It's the old trick of moving the part and seeing if the problem moves. If it does let me know and I'll scap a motor pulley off an SL machine which "should" work. The shutter pulley won't since there is not clutch on the SL's I have (and the shutter pullley on these military versions are plastic).

I think there is either an out of spec pulley on the machine or a belt that isn't riding in the groves.

John

Posted by John A. Pommon (Member # 292) on November 30, 2005, 04:05 AM:

I was able to clearly see that the belt is riding dead on in the grooves of both machines.

Looks like the motor mount has only three screws. . . . then unplug the two connectors and it's out.

Any suggestions on removing the belt? Unscrew the pulley & slide it off the shaft or simply pry/flip the belt off the motor pulley? [Eek!]

John P

[ December 01, 2005, 12:34 AM: Message edited by: John A. Pommon ]

Posted by John Whittle (Member # 22) on December 01, 2005, 12:28 PM:

quote:
Any suggestions on removing the belt?

If you can "walk" the belt so it's on the smallest of the two pulley ridges on both the shutter and the motor, it'll be easy to take off. Also if the motor is released, you can angle it slightly removing any pressure form the belt. You'll have to "walk" the belt on in any event when you re-install.

Not sure if you can remove the belt on this model without taking the cam tank out. Some models won't allow the belt to clear the back of the shutter pulley without removing the cam tank.

You might have a variation in motors, but far more likely is a variation in the pulley diameters. I though things were better when they finally went CNC, but tools still wear and a worn tool cutting the motor pulley would make a difference. It would be fine on it's own, but in a change-over system it would stand out.

Why not convert the machines to sync motors? Then you'll only have to call the power company if they're off speed.

John

Posted by John A. Pommon (Member # 292) on December 01, 2005, 08:17 PM:

quote:
It would be fine on it's own, but in a change-over system it would stand out.

Rod Taylor sounds a little lite in the loafers more like Uncle Martin [My Favorite Martian] than George the time travelor.

I gotta slow this baby down.

Thanks very much John for the help.

quote:
Why not convert the machines to sync motors? Then you'll only have to call the power company if they're off speed.

Not a bad idea. . . lock these babies up!!!

What's the frequency range variation of P. G & E. . . . . plus/minus one percent?
Pretty stable stuff huh.
John P

Posted by John A. Pommon (Member # 292) on December 04, 2005, 05:12 PM:

John - Got finished with work early.
Will pull & swap the motors. More at 11PM

Thanks
John

Posted by John A. Pommon (Member # 292) on December 04, 2005, 09:09 PM:

I transferred the motors (including the pulleys) . . . .
and the problem didn't transfer. (still 4:48 on the questionable machine. [Confused]

Posted by Jan Bister (Member # 332) on December 05, 2005, 09:52 PM:

I wonder.......

.... could it be possible that the tension from the take-up reel slows the mechanism down (introducing minor belt slippage etc.), and this is happening more on one machine and less on the other?

If you were to run your test film through both machines WITHOUT using the take-up reel, and winding up the film manually with a separate rewind or with another projector - would your two machines still exhibit the speed-difference phenomenon?

I think that's a question worth finding the answer to...

Posted by John A. Pommon (Member # 292) on December 06, 2005, 04:19 AM:

Hi Jan, I may take you up on your test but at the moment I don't think anything is dragging it down or pulling it faster.

The next thing I'm going to trade away [now that the motor module isn't it] shall be the 'transformer module'.

Who knows Jan . . I may end up swapping out the entire machine [Eek!]

It's just finding the time . . .

Posted by John Whittle (Member # 22) on December 06, 2005, 12:59 PM:

quote:
I transferred the motors (including the pulleys) . . . .
and the problem didn't transfer. (still 4:48 on the questionable machine.

Did you change the cam tank as well? (That's usually easier than pulling the shutter pulley since they changed the clutch assembly.)

If you changed both the motor and shutter pulley and the motor, then you have a possessed machine. The transformer doesn't have anything to do with the motor. Just unplug it from both machines for the test and see if you change the problem.

The new machine isn't one with "international" wiring by any chance? I've got one of those by some strange method and they're really wired differently than the US product.

John

Posted by Jan Bister (Member # 332) on December 06, 2005, 10:58 PM:

quote:
I may end up swapping out the entire machine

And end up with your other machine running too fast [Big Grin]

Posted by John A. Pommon (Member # 292) on December 08, 2005, 03:42 AM:

quote:
Did you change the cam tank as well? (That's usually easier than pulling the shutter pulley since they changed the clutch assembly.)

No, haven't swapped out the cam tank [yet].

quote:
(That's usually easier than pulling the shutter pulley since they changed the clutch assembly.)

The stop clutch and shutter pulley come off together with the cam tank assembly.

quote:
If you changed both the motor and shutter pulley and the motor, then you have a possessed machine.

So far I've exchanged just the motor with the motor-pulley on it's shaft.

The wiring for both machines is identical.

The cam tank including it's clutched shutter pulley is next.

Any ideas how these identical looking cam tank assys could affect the speed?

Thanks

John

Posted by John Whittle (Member # 22) on December 08, 2005, 09:35 AM:

quote:
Any ideas how these identical looking cam tank assys could affect the speed?

Yes, the pulley on the shutter shaft is slightly smaller than it should be. If you find some masking tape that you can wrap around the pulley and fit into the groves then that will enlarge it and make the projector run a little slower. The smaller the shutter pullley, the faster the projector will run since the motor pulley will turn at a constant speed. You might even rry the tape test before you remove it. If that's the problems (and you seem to have changed everything else) then you'll have to replace that part.

John

Posted by John A. Pommon (Member # 292) on December 08, 2005, 11:55 PM:

quote:
Yes, the pulley on the shutter shaft is slightly smaller than it should be.

I removed the cam tanks today . . . the pulleys look as if they match . . . interchanged the tanks. . . .

The "control" projector which 'ran' at normal speed now runs the 5 minute test film in 4:48.

The previosuly "fast" machine now runs the 5 min test in 04:56. [nearly the 5 minute mark].

Can a cam tank make this much difference?

[where's my micrometer] [Mad]

Posted by John Whittle (Member # 22) on December 09, 2005, 09:09 AM:

quote:
Can a cam tank make this much difference?

Yes, and you found the problem. It's the shutter pulley on that cam tank (nothing in the cam tank changes speeds). It doesn't take much to have that speed difference which is why I'd test it with masking tape to build up the small pulley and check the speed. Do one wrap and test and if still fast, add a second wrap and test.

Since I think they went to CNC, there are probably a lot of shutter pulleys around that run at that speed--or there was a slight change in the motor pulley and shutter pulley and you just have the wrong combination. But in any event, the fix is the shutter pulley from a "parts" machine. Unfortunately the SL machines that I have for parts don't have clutches and have have plastic shutter pulleys that have the shutter blade mounted to the pulley (no clutch parts). Also since the sprockets on the SL are a different size than the SSL, the worm gear is different on the cam tank shaft.

John

Posted by John A. Pommon (Member # 292) on December 09, 2005, 03:04 PM:

John, thanks for the technical support and explanations while I tare down these two machines & swap parts.

I started tinkering and put them both back together before
checking diameters closely with a "myc" . . . rats. . .

I'll look for a scrap SSL on eBay and take it's cam tank pully.
Thanks for your help . . you sure know this stuff inside out.

Regards,

John Pommon

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