70s DC Otis Geared machine, low generator output

The GSEF windings seem ok, the controller seems ok, but the there is hardly any output from the generator, even with speed relays and Q .
Any ideas anyone?

Possible High Mica on Generator bars, If this is a self excited field there is a rectifier in the loop circuit that will cause that. It has 3 leads on it.

Thanks for that. We had the generator pulled out and refurbished by a motor rewinder. Now its worse. Rolls up on inspection speed when driven up, stays in position when driven down. Very little output. Replaced the rectifier, no change. Not sure what to do here.

It sounds like you have lost polarity on the Generator fields. You should have 2 or 3 vdc with the generator sitting, idling on inspection. I would check for correct polarity. If you do not have the DCV, I would look at the AC feeding your rectifier, I am assuming you have rectified DC and not an exciter, if in fact, you have an exciter, you may need to flash the circuit with DC from another source. Just guessing since I do not have a print. With a print, you should be able to easily track down your lack of DCV.

Thanks John. It's a self exciting field. I've tried flashing with 12v, but not sure how long to flash it and what voltage. On inspection and idling I have millivolts only.

You may want to check for grounds, or something shorting your DCV.

The motor rewinder connected the shunt field backwards.
Now I have the lift running but it runs faster up than down by about 30%. How do I adjust that. I don't know which part of the circuit is responsible.

If you are running faster in the up than the down, you have to strengthen the series field by removing shunts, or in your case moving taps in the series field. I would not change the compounding until you have formed a glaze on the generator commutator. Also, make sure you have the correct brushes in the gen. The compounding is usually not the problem. If the brushes are new, look at the bottom to make sure they are completely shiny all the way across. They may need to be sanded in.

If your motor shop reversed the GSEF leads, you may need a connection diagram of the generator. They could also have series field wrong. What generator do you have listed on the metal tag on the generator end, TYPE? 63GA, 71GA, 82GA??

It's a 65 GA and they did have the series field wrong. I corrected that. Now just speed problem

Interesting, I never saw a 65 Generator. 65 Is a controller Type. 63, 71, 82 are generators.

I've attached the nameplate

Can you send a pic of the full generator? I asked the international Otis Field Engineer and he never heard of a 65 GA either. Could be miss stamped.

Heres the old one which is also 65GA. We've got three in total.

That sure looks like a 63 GA. The 63 changes series field taps with a wire GSF to GSF2 is 3 turns per pole. GSF to GSF 1 is 4 turns per pole. GSF 2 to GSF1 is one turn per pole. So you end up with 12 turns on GSF to GSF 2 and 16 turns from GSF to GSF1 and 4 turns from GSF2 to GSF1. The 71 GA and 82 GA have taps on each pole piece to change Turns. If your in New Zealand, your stuff probably came from the UK. I adjusted a 3 car group and a service car on the Grand Bahama Island and their stuff came from UK. Everything was a mess from there,As your glaze gets stronger your compounding will get weaker with the increase in loop circuit resistance. If you run out of turns and still need stronger compounding, you can shift the ring a 1/16th off neutral and against the rotation will make it stronger. With the rotation will make it weaker. Very common to shift ring on a 63 as your control is limited. Can only do so much with the bedspring shunt on back of controller .

Have you checked or reset neutral yourself? I’ve found it off so many times coming back from the motor shop that now I just check it as a rule.

I'll get back to you guys. Today we changed taps on the series field and the best result was slow up no down, even with 55 amp loop current! Very strange. Will try moving the ring. We haven't checked neutral yet though.

Do you have a diagram for the field connections for that generator yet? There may be more wired wrong from the motor shop. A shunt field, series field or innerpole wired backwards. Reminds me of a nightmare with a giant Otis gen we had come back from the motor shop all kinds of F’d up. At least you have other cars to compare. This was a 14 stop freestanding tower to nowhere but that’s another story.

So now, as soon as the generator is powered up it almost stalls like its loaded up and a lot of current through the loop circuit even with GSEF disconnected.

Your GSEF is backwards to the Series field. reverse the leads, then use the leveling field leads to make sure car runs right direction. If wrong reverse them. You cannot disconnect the series field to stop build up. It is wound in the pole piece.

Do everything on inspection and use Uor D and H for leveling field.

Thanks Rolly, I will check that.

Even with GSEF and GLF disconnected the generator is outputting 27v and almost stalling, brush holders get hot. I cant see how it can generate with no fields. Any ideas on this?

You cannot disconnect the series field from the GSEF. It is wound in the pole piece so the self excited field can build. If you listen and do what I told you can get all the fields in sync, The suicide circuit using the SUD relay could have an open resistor. Also on some controllers a breaking contact on H is used in suicide circuit, Does you generaror have taps on the pole pieces, or an extra series field wire coming out to controller. There is no 65 Generator, some dumb ass in the UK stamped it wrong. I had 4 controllers in the Bahamas from UK and I had never seen so many factory wiring mistakes. First time power was applied transformers smoked for touch buttons. Awful Quality. You will notice there is no way for the GSEF to get any external power to the field, it is done with induction via the leveling field to get the build up started. Also all the speed steps pull in all at once,

Was this issue ever resolved?