Lyrec Motor Capacitor Question

[opcode66]

I'm curious if mine is the correct value or not. It seems to be a motor run capacitor. It is valued at 20mfd and 300V. I am on the 60hz 120V American electrical standard. I think my capacitor is starting to go. I would like to replace it.

I see a temco 20mfd (+-6 tolerance) at 370V
http://www.ebay.com/itm/260868393613?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Is this a proper replacement?

I see on the diagram for the PS66 programmer that there is a C11. It's value is specified as 10mfd at 220V. So, should I get a 10mfd or a 20mfd. 370V seems to be the only value I can get this style of capacitor in, so not much choice there.

[leo gonzalez]

i think 20mfd is the start cap value. 10-12 i think should be fine for american Voltage and freq.


Sent from my iPhone using Tapatalk

[Greg Reierson]

I'm far from the studio for the next week but I just changed mine after noticing a bit of motor vibration. I spent hours conferring, comparing and contrasting advice with Chris Muth, Paul Gold, Josh Bonati, Dylan Constan Wahl and a local motor guy (thanks guys!). It seems to be a moving target and there are various configurations out there.

First, don't confuse the run cap with the start motor cap. The run cap is up by the autoformer. The start cap is mounted on the motor. It a bit hard to specify the capacitor value without jumping through a few hoops. Do two things:

1) Check the current in the two coils of the motor. I don't remember which terminals they are at the moment. Something like q r s t - repeated for each speed. Two of them are common and the other two are for each of the coils. The current draw should be equal. Pop your DVM set to AC current in line with the first coil. Get a reading. Do the other. Mine were 0.4A and 0.48A with the original 4uF run cap. I put a 3uF cap in and got the second coil down under 0.4A. Dylan suggested getting a few 0.5uF and 1uF 630V caps (think tube amp caps) and play around with combinations until I found the sweet spot. He built a decade capacitor that could switch down to 0.01uF increments to really dial his in. The goal is minimal motor vibration. I got the second coil current to 0.4A and all is well. But wait, there's more...

2) Look at the phase difference between the two coils. These motors are wound to run on a 3 phase system - but only use two legs of the 3 phase feed. That means the phase difference from coil 1 to coil 2 should be 120 degrees. Since we all use single phase AC feeds, the motor run capacitor creates the phase swing in the second coil. When I first looked at mine it was closer to 90 degrees. Getting the coil current draw balanced moved it out to about 100 or so. It's working fine but I may still play around with the cap to see what it take to get it closer to 120 degrees.

Take a look at those two things and see what you get.

[opcode66]

Yup, I was looking at the start cap. Duh! The other cap next to the big transformer in the console cabinet to the left of the motor is the one I should be looking at. Though, I think I'd like to replace both.

[leo gonzalez]

why do you want to change the caps?

alsothe coils also do age as well and phase alignment becomes irrelevant...


Sent from my iPhone using Tapatalk

[Greg Reierson]

I'm not sure I can see how the phase alignment of the motor coils could change, but if that were to happen then that would be a good reason to try to find the best run cap to match. My gut feeling is that the phase alignment is more important than the coil current balance and a few motor guys I've talked to agree. Chris told me the manual says to balance the current. I have yet to try it both ways to see which runs the smoothest.

In my case, I have a 230VAC 50Hz lathe with a 60Hz motor running on a step-up transformer. I can only guess they got the run cap slightly off (or didn't bother to change it at all) when they did the conversion. The drawings vary widely, from 3uF up to 20uF, depending on motor, voltage, line frequency, etc. Experimentation is probably the best way to optimize it.

[Greg Reierson]

the coils also do age as well and phase alignment becomes irrelevant...

Phase alignment is what makes the motor turn. Not irrelevant.

[leo gonzalez]

yes, if not motor doesnt sync.

but If one the coils is in bad shape or a bit worn out, then its going to be difficult to get same values independently from how close to 120 is that phase. I dont think the current value depends on the phase value (phill collins?) relationship between the coils.

I had one coil on the 33.3 ring that i ended swpaping for one of the 78s which were mint compared to the others

anyways,
the value should be somewhere from 10-12 uf for the run cap @ 110/120V 60hz not 3.
3-4 could be for 220V at 50hz.

L.

[smithadamm]

I'm bumping an old thread rather than starting one, sorry if that is the wrong way to go about this. I'm wiring up a lyrec sm8-3a. I'm using the factory diagrams Dr. Dub uploaded. Looking over the diagrams, there are a couple of things that are unclear or not really included in the drawings and that I'm guessing on, so I wanted to get some advice from some veterans.

I'm assuming the two red and two white/yellow wires coming out of the top of the motor are for the start motor. I'm also assuming the DP4T switch on the start motor in the factory diagram is an internal centrifugal switch or something like that and I basically don't have to worry about it. I'm unclear as to what the two pole "1-2" barrier strip on the side of the motor attaches to internally.

I'm attaching a point to point wiring diagram as well as the factory diagram I'm working from, sorry if mine is kind of crude.

Any advice would be appreciated.

[smithadamm]

Nevermind, got it figured out. The start motor was tripping me up. Not automatic. It's more like starting an old hammond organ with the start/run switch. Also, I put it together that the 1-2 is just a barrier strip to hook the start motor to the start capacitor and doesn't hook to anything internal.

[petrolio]

Hallo trolls!
I was checking deeply My lyrec motor in those days , 50hz 220 volt... Wow never met a motor like this, the circuit was ok , CAP ok, coils and insulating of the phases good. Anyway
It was not turnig right. In the end I realized that you have to spin it manually until the selected speed and than switch it on... It works! Do you have the same experience?
I'm just a newbie...
The motor go to 50'celsius during work , it's normal i think,
In my workshop i have almost 232 volt , is it Too much?

Looking for a replace neon lamp for the platter speed , any idea?never sow like this before...

Good work to all trolls!!!



Inviato dal mio iPhone utilizzando Tapatalk

[dubcutter89]

Yes, the Lyrec Motor is a synchronous type of motor so it can only spin if it was brought up to/or over nominal speed. Therefore you have a starting motor (which almost nobody uses, or in a lot of cases is dead) or you use your muscles to get it going.

This is 1940 ies technology - a little less comfort, and a big piece of iron which probably will run forever...

Lukas

[petrolio]

Thanks Lukas!
Do you think is better to use a step down trasformer for the main ? ( the voltage where i live i 235 volt)

Petrolio


Inviato dal mio iPhone utilizzando Tapatalk

[opcode66]

I've followed the advice of Greg Rierson and have greatly stabilized the speed of my motor. My resulting Groove Graphic cuts are coming out much better. Still not as perfect as when cut with a digitally controlled platter motor. But, much better than what they were. Upon moving to L.A. I have found that my Lyrec was running much worse than it did in Chicago.

I'm working on a video detailing everything that I did. I will post it soon.