neutral wire for 3 phase

[wantacoe]

I bought a Kaeser model AB 1000 air compressor. 7.5 hp, 3 phase. I was told that you can run a neutral wire to make it single phase. If true is that a permanent fix? If not is it ok just to test the compressor. I bought it at an auction "as is". I would like to know if it is any good before spending more money on it. Thanks for any info.

 

[LXCam]

Does it have a built in vfd? Post a pic of the schematic.

 

[wantacoe]

Pics. I don't think it has a vfd.

 

[Bert_]

It has no use for a neutral and it won't make it run on 1 phase.

 

[LXCam]

Nope, no vfd and no it won’t work directly off single phase. You’ll need either need a vfd which is the way I’d go or a rotary phase converter. And being 7.5HP utilizing a soft start feature with a controlled unloader valve would be a good thing.

There’s a good vfd thread floating around, I’ll see if I can find it.

 

[Firebrick43]

They lied to you

 

[LXCam]

Here’s where I’m sure you’ll find some good suggestions. Id dial it in better but doing it off my phone ain’t gonna happen.

Show us your VFD conversions/installations

If you have the name/picture of the VFD, then some guidance could be provided as to programming. HY VFD's PD003 Main Frequency 60.00 PD004 Base Frequency 60.00 PD005 Max Operating Frequency 60.00 PD075 Higher Analog Frequency 60.00 The issue is a VFD is not a 3 phase power source to run...

www.garagejournal.com

 

[Walkers]

Sure, just run a neutral to the J box and then simply rewind the fields for single phase. Easy Peezy!

 

[LXCam]

Btw, if you want to know if it works before you do more with it. Go rent a smallish generator and test it out. Most rental yards have towable 50kw units.

 

[Terry D]

That compressor will not run on single phase the way it sets

 

[PoorUB]

Keep in mind if you go with a VFD you need to put the VFD in place of the contactor in the schematic. Most all VFD's do not like power being cut off on the output side. I would also disable the overloads as the VFD will handle that duty.

 

[Norcal]

VFD’s are not well suited for phase conversion on a air compressor, a RPC, rotary phase converter would be better.

 

[sparky 1971]

Yep, as stated a neutral won't fix anything. On another note, I have a customer with 2500 semi trucks on the road. About six or seven years ago, they got on a Kaeser compressor kick. I wired three 10 and two 15 horsepower units in about a six month span. Within three years, they replaced all of them except one of the 10 horse units, and the remaining unit would get replaced, but it's too big of a pita to get it out of the room that was built around it and it's only used a couple of hours a day for the paint booth. The maintenance supervisor told me they were the biggest pos ever made. I have to admit to not knowing what the problem(s) were, but that's a lot of money to spend because of small problems so it had to be a big deal.

 

[wantacoe]

Yep, as stated a neutral won't fix anything. On another note, I have a customer with 2500 semi trucks on the road. About six or seven years ago, they got on a Kaeser compressor kick. I wired three 10 and two 15 horsepower units in about a six month span. Within three years, they replaced all of them except one of the 10 horse units, and the remaining unit would get replaced, but it's too big of a pita to get it out of the room that was built around it and it's only used a couple of hours a day for the paint booth. The maintenance supervisor told me they were the biggest pos ever made. I have to admit to not knowing what the problem(s) were, but that's a lot of money to spend because of small problems so it had to be a big deal.

Ouch, Chances are mine is scrap too. Thats why I want to check it before I get in any deeper. It is either a 1996 or 99 model with 3500 hours on it, that is if the hour meter was still working.

 

[wantacoe]

On a side note, Does anyone know why these divorced tanks are made to look like a rocket instead of having legs extending from the side like most tanks?

 

[yatg]

I bought it at an auction "as is".

Out of curiosity, how much are you into it for?

 

[pancho400cid]

Does anyone know why these divorced tanks are made to look like a rocket instead of having legs extending from the side like most tanks?

Because for the particular manufacturer of those tanks, rolling/welding sheet steel was cheaper than stamping legs or buying legs from an outside supplier.

Looks like they made it a little extra-far off the floor for valve access or something.

..

 

[sparky 1971]

Ouch, Chances are mine is scrap too. Thats why I want to check it before I get in any deeper. It is either a 1996 or 99 model with 3500 hours on it, that is if the hour meter was still working.

You wouldn't happen to know someone that has a shop with a three phase service would you? I don't know how big of a pita it would be to load it on a trailer or flatbed and take it to the power supply, but that's the most cost effective way I can think to check it out.

 

[wantacoe]

Out of curiosity, how much are you into it for?

I don't think I am in too bad of shape, about 800. It was an online auction and I missed the preview day. It was advertised as a screw compressor, that is why I bid on it.

 

[wyliesdiesels]

Someone fed you a load of BS... neutral is for 120v single phase or 277v single phase