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Joined: Jul 2004
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cgw Offline OP
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Anyone used a rotary phase converter for a 240/208 3 phase elevator in a building with 240V-1 ph? Any issues I should be aware of?

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We used to use a bunch of them in the computer business back when computers filled the room. They went from 208 60hz 3/p to 208 400hz 3/p tho. Same basic machine.


Greg Fretwell
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New install? If so, why not use a modern VFD. Less maintainance, possibly greater reliability, more flexibility, smaller size, less audible noise, etc.

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I've NEVER seen an elevator install/ upgrade which permitted outsiders ( non-elevator technicians ) to touch ANY aspect of their sub-system.

That specifically includes phase conversion/ rectification and transformations.

The latest Otis Elevators are entirely dialed into 480 VAC power. When 208Y120 is Service Power -- they install their own step-up transformer.

The much older Otis Elevator, being replaced, used a rotary rectifier: namely a motor-generator set. It'd spool up before the doors would even open.

Until the modern electronic era, only DC motors were considered suitable for traction effect.

Now, step-wise, these are all being replaced by smart AC motors.

BART hauled its old cars off to the factory to be rebuilt with them.

Likewise the entire railroad fleet is being shunted oven to AC.

I wouldn't even consider using a rotary phase converter for elevator duty.

Perhaps you're looking at / thinking of a motor-generator set.


Tesla
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Originally Posted by gfretwell
We used to use a bunch of them in the computer business back when computers filled the room. They went from 208 60hz 3/p to 208 400hz 3/p tho. Same basic machine.


Your talking about a motor generator, a RPC uses a 3 motor to manufacture a phase from a single phase supply to operate 3 motors on a 1 supply. Most are self starting, some home built models use a "pony motor" to bring them up to speed, & then idle them, (all of them single phase the idler motor).

There are plans out there for folks building their own RPC's, there are a lot of people who never heard of RPC's, here is a link to 1 forum that has plans for them. http://www.practicalmachinist.com/v...ry-phase-converter-designs-plans-101231/

Some people are a bit too "clever" for their own good, but that would be a good topic for a thread on it's own.

Off topic but since a lot of people have never heard of RPC's......

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Quote
Your talking about a motor generator, a RPC uses a 3 motor to manufacture a phase from a single phase supply to operate 3 motors on a 1 supply.


You are right, my bad. We did use a MG


Greg Fretwell
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Originally Posted by gfretwell
Quote
Your talking about a motor generator, a RPC uses a 3 motor to manufacture a phase from a single phase supply to operate 3 motors on a 1 supply.


You are right, my bad. We did use a MG


At a former employer we had a 100 HP MG set for 400HZ power, it was a PITA to cool the room where the transformer & MG set was, it was later replaced w/ a inverter....

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They usually got the 400hz inverter supplies along with the UPS when they went that way.

The MG sets were pretty much trouble free tho.


Greg Fretwell
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cgw Offline OP
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Are we still on topic?
An existing building with 240V-1Ph. The new elevator is 208/240V-3ph.
American Rotary and Phase-a-matic are two manufacturers of rotary phase converters.

Someone mentioned a VFD. Can a variable frequency drive be used?

I have yet to meet a elevator manufacturer who would install anything on the line side of their equipment (like a transformer).

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Functionally a VFD should work fine. I am not sure if the elevator supplier/inspector is OK with it but I am not sure why they wouldn't like it.


Greg Fretwell
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