Single Phase Elevator?

[Npstewart]

Adding a 25 HP elevator to a multi family complex that only has single phase power... I never saw a single phase elevator, especially one that is 25HP! Would a phase converter be possible here? Or should I tell them we need to talk to the utility company.

 

[Volta]

Might consider an additional service for this load, but if the elevator company can come up with a M-G set, single phase might be possible. I would guess 130 amps or so on a 240 volt system.

 

[Npstewart]

I think your right, this should come off the house panel, ill see if I can do a new 3 phase service. I couldn't see something like an elevator running off of a phase converter, although I know it has been done before.

 

[Jraef]

I don't know of anyone who even makes a 25HP 1 phase motor.

If it is a Hydraulic elevator, you could use a 3 phase motor and power it from a VFD. But the VFD would need to be 50HP for powering from a 1 phase supply, so that means the maximum input current will be around 145A. I mention this because the NEC says you must base the circuit sizing on 125% of their MAXIMUM input current rating of the VFD (not the load FLA). So to do this from a 1 phase supply, you will need a 200A service all by itself.

If it's a traction elevator, then that is not going to work*. If it's a DC traction elevator, you would have to check with the supplier to see if that will be compatible with a 1 phase supply, some DC drives are not. If it's an AC traction elevator, then someone is probably having a custom 1 phase 25HP motor made and you will have a hard time starting that Across-the-Line in my opinion.

*Traction elevators need specialized power control not common on VFDs, i.e. with regards to what happens if it fails. There are VFDs available for traction elevators, but they are typically only sold by the elevator suppliers because of liability issues.

 

[LarryFine]

I concur with the separate-supply guys.

If the existing 1ph house-panel's service could otherwise handle the current, maybe the POCO will just add one transformer and give you a high-leg Delta.

 

[Ragin Cajun]

I just did an apartment where it had a 25HP elevator. Service to the "area" was single phase. Utility wanted $30K for three phase but based on "issues" with a previous elevator, the owner went with it.

RC

 

[Npstewart]

I talked to the manufactuer and he said the only thing they can do it change it to a 12HP single phase motor, he said the elevator would go extremely slow.

 

[hillbilly1]

I installed a small single phase elevator in a church, I had a three phase delta service, but somebody sold them a single phase elevator, the motor was three phase with a VFD. I had to double my wire size over to it, and of course it was at the far opposite corner of the church where they put it. Of course everything else got put over there too, all six A/C units, the office package ect. I had roughed the slab with an 1 1/2 conduit turned up in each corner from the electrical room because I was told the A/C's were going to be split up that way. (they were single phase also)

 

[Open Neutral]

Note utility may want to apply their special tariff for elevators.

They do so because they want extra $$$ for service with such a poor peak-to-average profile; they must provide for peaks, and you only want to use it 10 min/day total.

[Last century, the utility supplied DC for elevators. ConEd dropped theirs in 2007!

 

[Npstewart]

I spoke with the utility company and we are doing a new 3 phase service. Im waiting on whether what type of service it will be.

Im assuming this will be a standard 208y-3 service. My plan is to run the new service to a exterior fused disconnect and feed a new panel with it to pick up the new 25HP motor and the single phase loads such as pit etc. Just thought I would put an update out

 

[LarryFine]

Im assuming this will be a standard 208y-3 service.

I'd be surprised if it was anything else, except the afore-mentioned open-Delta conversion.

 

[Dennis Alwon]

I talked to the manufactuer and he said the only thing they can do it change it to a 12HP single phase motor, he said the elevator would go extremely slow.

Wow-- 240v single phase motor is not even listed in T. 430.248

 

[Npstewart]

Yea, this guy isn't very knowledgable to tell you the truth. I think the largest single phase motor is actually 10HP which is the last HP listed in the table.