Film-Tech Forum ARCHIVE: Motor Woes on my Century C Projector

This is topic Motor Woes on my Century C Projector in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Mark Farr-Nash (Member # 4233) on 12-28-2007, 10:23 AM:

Here's something that sucks:

I turned my projector on last night and everything came on BUT the motor. This was weird, because when I threaded the film, it turned as smoothly as it always does. Then I noticed and smelled the smoke. I powered everything down, opened up the box that connects the tower to the motor, and let it cool down. This morning, I had my local electrician come by to test the lines. Sure enough, they were getting juice. The problem is in the motor.

Now, I'm stuck with trying to get someone local to crack it open and see if it can be fixed, or pick up and install a new/refurbished motor. I seem to remember one of the techs telling me that the motor that drives the projector isn't specific to the theater industry. But again, here's the deal: both of my techs are not answering their phones, and the one guy who could help me at my supplier is out sick.

I could really use some advice on this one. My motor specs are as follows: it's a Robbins & Myers, Type KS, serial number MM4241 CM. Any thoughts? Tips? Advice?

Thanks in advance,

Mark

Posted by Scott Norwood (Member # 30) on 12-28-2007, 10:32 AM:

Look in the Yellow Pages under "Electric Motors" or "Motors - Electric" and start calling; pretty much any competent motor shop can test and repair these. It shouldn't be terribly expensive or difficult.

Does it run properly if you remove the load (remove belt or coupling to soundhead)?

Posted by Tim Reed (Member # 137) on 12-28-2007, 10:53 AM:

Scott's right. That's probably the easiest thing to do. Off hand, I'd say it's something with the start winding/capacitor/switch/circuit... depending on the particular installation you have.

Some Centurys also had a slow start kit, which was a resistor in series with the start winding. This would be in a small 4"x4" box mounted on, or near, the motor itself. That resistor may have opened. (Although, if it's a Robbins and Myers motor, then you may not have Century soundhead, since that could be an SH-1000, RCA, or Motiograph.)

Posted by Steve Guttag (Member # 268) on 12-28-2007, 11:24 AM:

Wolk also stocks the "MO-40" async motor for the Century. I believe it is a J56 frame motor (key to ensuring that it will be the right dimensions). Also key is that it is 120V single phase with 1/4 HP. I much prefer the slow start on these as banging the machine on plays havoc on the gears.

Posted by Gordon McLeod (Member # 33) on 12-28-2007, 12:49 PM:

Odd as usually Century soundheads had Hoover (old ones) GE Westinghhouse or Century Motors on the later ones
Robins were usually on RCA soundheads as a general rule
It is probably the starter switch in the motor that failed and the question is did it burn the winding opens

Posted by Mark Gulbrandsen (Member # 72) on 12-28-2007, 12:59 PM:

There is a 56 frame motor that is available "off the shelf" from any large motor distributor that will fit the Century. I think GE makes one that fits. Its not really worth getting that old motor rewound... many times the start switch is NLA. If you're not familiar with electric motors best thing is to have an electrician remove it for you then take it in for testing. Many times the shop you are having it tested at can also supply you with a new motor that will fit. On the C model I would stay away from capacitor start and go with a split phase type of motor as they run up slower and are much easier on the gear train at startup.

If it turns out that you have a Robbins and Meyers motor and an RCA MI9030 sound head then Wolk is your ONLY source for a new motor. Cost is about 450.00 give or take. If you have an RCA then look at the front of the soundhead for the model plate... it should have an MI-xxxx number on it.

Gord, The only Century Soudheads I've ever seen with Hoover Motors wre the Canadian built versions. Some obviously trickled down to the states but the ones here mainly had Century Electric motors on them... go figure...

Mark

Posted by Mark Farr-Nash (Member # 4233) on 12-28-2007, 01:40 PM:

Thanks, guys, for the feedback. I've got a small motor specialist coming in to look at it. He'll most likely take it back to the shop. He's estimating having it back to me by Sunday.

And in answer to the other question, I have Sony soundheads. Don't know if that affects the equation or not.

Mark

Posted by Louis Bornwasser (Member # 3063) on 12-28-2007, 02:04 PM:

BTW: Hoovers were standard on the R3 soundhead and earlier R3B machines. Later, Century was "normal." (THe early soundheads had sleeve bearings on the main shaft.) Louis

Posted by Sam D. Chavez (Member # 1841) on 12-28-2007, 02:56 PM:

I saw lots of Hoover motors and even chain drive instead of belt drive on early sound heads

Posted by Tim Reed (Member # 137) on 12-28-2007, 04:52 PM:

quote: Mark Gulbrandsen
If you have an RCA then look at the front of the soundhead for the model plate... it should have an MI-xxxx number on it.

Every RCA ID plate I ever saw was on the back...

Posted by Mark Gulbrandsen (Member # 72) on 12-28-2007, 08:54 PM:

I have yet to see one around this neck of the woods... nor in the Midwest area except those that I brought back form north of the border. MOst of the Century's were in GC houses and all those were either Century Electric or GE sync motors on the JJ's... also I seem to remember a few Westinghouses thrown in.

Mark

Posted by Robert Throop (Member # 61) on 12-28-2007, 08:57 PM:

quote: Sam D. Chavez
I saw lots of Hoover motors and even chain drive instead of belt drive on early sound heads

I used to have a pair of R5's with silent chain drive.
Bob

Posted by Louis Bornwasser (Member # 3063) on 12-29-2007, 07:43 AM:

GC qualifies as "recent times." Century R3 & R3B from about the beginning until about 1960 used Hoover motors. The wood are full of them (small indoors & drive ins) here.

We usually rebuild the Hoovers, since we have such a large num ber of spares. The motor mounting plate is quite different; the old ones have slots, not tapped holes like the ones that had Century (no relation) motors. Louis

Posted by Steven J Hart (Member # 2340) on 12-29-2007, 11:02 AM:

quote: Mark Farr-Nash
And in answer to the other question, I have Sony soundheads. Don't know if that affects the equation or not.

What the heck is a Sony soundhead? I've never seen one.
Steve

Posted by Mark Gulbrandsen (Member # 72) on 12-29-2007, 12:06 PM:

quote: Louis Bornwasser
GC qualifies as "recent times." Century R3 & R3B from about the beginning until about 1960 used Hoover motors.

I don't go back to the 60's... I started in this biz right about 1980. The closest GC I did some work at was in Lombard and it was built in 64 as a twin but was later split up and more screens added. Its since been replaced by a huge plex. Off hand I only remember there being one pair of JJ's there, the rest were SA's. Chicago was mainly a Brenkert/RCA town with a sprinkle of everything else thrown in here and there. VEry few Century's except for the GC locations.

quote: Steven J Hart
What the heck is a Sony soundhead? I've never seen one.

He has Sony SDDS digital sound.... This is actually the penthouse he is referring to.

Mark

Posted by Timothy Eiler (Member # 383) on 12-29-2007, 07:41 PM:

quote: Sam D. Chavez
I saw lots of Hoover motors and even chain drive instead of belt drive on early sound heads

I got 4 screens with chains. They came out a Pacific Theatre then went into a reopened GCC that lasted for 5-6 years then into my drive in in 98. I also still use the orange ORC consul that I bought with them

Posted by Bill Enos (Member # 440) on 12-29-2007, 07:51 PM:

Rewinding that motor could easily cost several times what you would pay for a replacement if one is available. If a drop in replacement can be had toss the dead motor.