Electric Motors/1950's Leland repulsion induction motor
QUESTION: Looking to help out a handicapped friend that purchased a house with an elevator that needs the motor replaced. Any info would be greatly appreciated. Its a Leland repulsion induction motor, Type RD, 1/2 hp,FR. 4c66z, 230 v., Duty 1/2hr, 8.8 amp,1725 rpm, PH 1, CY 60,Ref.14052 PU 4777
We are at our wits end. I priced conversions to the system but it was totally out of his price range. Thanks for any help you can give and God Bless.
ANSWER: You did not get my first reply? Let me know, I want to make sure you got it,
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Wonder what happened to that that was long real long,
Ok anytime you talk about moving human beings $$$$$ liability in everything, so in order to make this thing work, you gotta fly under the radar,
I need to know this
That is an expensive motor even a new one can be had, but cost is way up there for just general purpose, add on moving a human elevator duty, lift duty five time the price and it is the same damn thing
Who says it needs to be replaced? Why what is wrong?
The techs who know jack about repulsion induction are few and far in between,
Do we have service report saying the brush mechanism is worn out, the fields are shorted the rotating armature/rotor is shorted what is the problem?
YOU least expensive way out of this is to fix what you have which is a low end RPM high torque but able to accelerate to a running speed, coast and brake.
We need to start with either removing this motor from the picture or simply fixing it and done,
I don't know who said what is right or wrong, but not many elevator guys are motor guys they are elevator guys ever seen an elevator penthouse? They understand THEIR MOTORS, but not the internals and how to fix them they can identify what is wrong maintanance that kind of thing, but I see this all the time all the time for 4 decades
Something with a motor doesn't do whatever gotta be the motor, hell it aint even half the time it is really the motor
I would say the motor might not be performing but did anyone check the contacts and check for voltage drop to the motor at the motor?
Find that out, if we got nameplate voltage at the motor, then a repulsion induction motor fails in these modes, brushes get short loose spring tension, arc, arc burns more brush shunts, spring, brush surfaces it stops working,
I need to know what is wrong with the motor not it needs replaced, and that is what you are going to get from most places because it is old technology but damn good technology and with a bit of maintenance and keeping the contactor in good shape the brushes at a reasonable length they can go for a 100 years easy,
They are great devices for the purpose they were designed and are hard to find,
So lets start there,
Next an interface is not a huge deal, you can put a half horse induction motor in place, install a VFD Variable Frequency Drive, interface it to the up and down controls and done
Stair lifts dont have complex priorities on calls who has been waiting to go up in elevator one versus elevator eight so no need for a PLC< the VFD, it depends on brand and so on but at 230 volt and most are able to convert 110 to 220 right in the VFD and no transformer is needed, most have around 40 to fifty user defined paramenters not a huge thing,
The main parameters are ramp up speed, so you don't jerk the chair on accel down or up, coast, overload inside, a setup of parameters, so that it starts up at 20 hertz accels to 60 in x seconds, can be set for a predetermined amount of length revolutions, whatever, it then decels and coasts into the limit top or bottom brake is set, reverses is ready to go the other direction,
But then you got a cheap CHINA Made 1/2 HP tin can motor, that will do the trick I would find a used surplus cast iron frame old one yours is a 66 frame really a 66Z FRAME WHICH MEANS THE OUTPUT SHAFT IS NOT STANDARD TO WHAT STANDARDS THEY DID HAVE BACK THEN, IT PROBABLY MEANS IT HAS SOME KIND OF EITHER STEPPED SHAFT OR GEARED SHAFT CUT RIGHT INTO THE MAIN ROTOR SHAFT WHICH SLIPS INTO A GEAR CASE, z MEANS NOT STANDARD SHAFT, DONT SAY WHAT JUST IT IS NOT STANDARD 66 FRAME DIMENSIONS,
Now there are way to get around that use the old motor shaft as the drive pinion machine a shoulder for a pulley and go it that way, push a new shaft into the new motor matching existing,
Drive around $300 or so but remember it has a NEMA ONE Enclosure, overload protection reversing, 40 more parameters you dont have now, so it is workable, and you buy it like you are driving a pump or something there should be other centrifugal or friction safeties on the lift on top of the motor brake,
But I say lets find out what is really wrong, if we can fix the existing motor and clean up any burnt contactors on your reversing mechanism, that is you most cost effective fix hands down, but until I know for sure what is wrong, we can only guess the worst everything is burnt up, now we go and find a used surplus with the same dimensions if not modify, install and done,
If YOU WANTED TO UPGRADE to fancy VFD the ride is better I understand more detailed ramping and decel so smoother plus speed control which there are limits provided by your local KING we got a lot of them now days so gotta do what the king wants, so stay under the radar it is just as safe efficient, as the existing,
HOw is the rest of the lift, brake, rails, seat, controls, so on?
NEw lifts are built with VFDS from the get go, and I have seen some amazing prices for a standard weight one floor lift INSTALLED IN A DAY which I could see that happening
But you want low low cost then fix the motor, if not reasonable we look for a surplus motor that is in running shape hopefully has the same worm shaft, step shaft, double shaft, whatever if not modify it, plus it in and go,
Next put your old mechanical parts driven with a VFD, and a new modern frame motor,
There are going to be codes, and not many can be danced but if you stay on the straight and narrow no extra bells and whistles if it load tests it usually passes in most places around the country
There is a fix to this, I cannot guarantee it is going to be dirt cheap I can guarantee we will look from the least expensive option and go up as needed
Get me a motor evaul report on that motor, once we get any info, great if not we ask for some,
Let me know