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Posted By Topic: Mystery Air Compressor

Mar 25 2019 17:50

I just bought this massive air compressor after the seller insisted it was for single phase power supply. It's a Hitachi Bebicon brand and most of the writing on labels etc is in Japanese. I need some help determining if this will actually run on single phase. I have serious doubts. I have attached an image and a link to the same item found online. If anyone can help with this, it would be very much appreciated.

If it turns out that it is dual or three phase, what would be needed to permit it to run on ordinary NZ household power supply. I've a feeling it would blow every fuse in the house and burn it to the ground.

Kind regards,

Mar 25 2019 18:48

Update: Just used google translate and I'm pretty sure this is a 2-phase compressor. How much would it cost to get 2-phase installed in the house? Is there a way around this? Just googled products like FASTEC Start and they seem to workable only up to 5.5KW. This compressor is 7.5KW.

Mar 25 2019 19:26

60Hz could be a problem too

Mar 25 2019 19:48

I never realised how disfunctional the Japanese power grid is. 2 phase there is about 200v. Single phase here. They seem to allow 10% tolerance so 220v. Still below 230v. I have worked on some Japanese motors in a machine and we powered them by a VFD. Problem solved. Either that or just fit a local motor. Only issue may be starting current at single phase so perhaps a VFD is a better option to also control starting current.

Mar 25 2019 20:05

Top line says 2 stage, 7.5kW, 3 phase.

But it will be 3 phase 200-220V, not 400V.

Easiest fix would be to pick up another 3 phase motor from an electrical scrap merchant. There's one in Dunedin called Rietveld. They have hundreds of 3ph motors.

You'll probably have to change the starter as well though.

Looks like a high price for that size compressor though...??

Mar 25 2019 22:42

DougP, you're right, 2 stage, 3 phase is what it says. I'm just gonna re-sell it to someone with 3 phase. I knew it was too good to be true - a compressor that size capable of running on single phase.

Mar 27 2019 18:42

If it says two phase, it likely means split phase - 100V to neutral, 200V line to line. Common in Japan and US (at 120/240V).

Still single phase and will probably work at 230V, except that a) 60Hz, b) that's a very big motor for a 63A mains supply, and c) probably only rated for 125V to earth.

Get a three phase compressor with a star-wired motor, change it to delta, and put a 230V VSD on it.