How do phase converters work?

[sambotc]

Might have a chance of an interesting new career on Monday. Part of the equipment they install uses 3 phase, but from what I can gather, they use a single phase supply, which then goes through a phase converter to create a 3 phase supply for the equipment?

Just wondering if anyone could briefly explain how this is done so i can have some understanding before going into the interview!

Thanks in advance

 

[johnboy6083]

there are two types as far as im aware. One is a rotary convertor, which is a motor generator. One motor is supplied from the standard power supply, and this then rotates the generator.

The other type uses capacitors. I believe that some VSD's can also supply 3ph from 1ph.

 

[Rockingit]

Clever electronics can also generate pseudo 3ph simply by splitting the input signal and then delaying the output by 120degs (so effectively 150uS) before recombining them, but the issue tends to be that it's no good for heavier current demands.

 

[sambotc]

Clever electronics can also generate pseudo 3ph simply by splitting the input signal and then delaying the output by 120degs (so effectively 150uS) before recombining them, but the issue tends to be that it's no good for heavier current demands.

Thanks for the replies, This is how I imagined it working. johnnyboy, are you saying the other kind is a single phase powered motor/ generator with 3 phase windings? If so is it a fairly efficient way of producing 3 phase? Would this be more reliable than the 'clever electronic' type?

 

[Knobhead]

Single phase converters are basically a rectifier feeding a DC bus which in turn feeds three inverters. OK if you want 230V three phase. If you want 400V then you have to go for a two stage inverter and the price goes through the roof.

Good luck in the job, but do some searching on Google before you start.

 

[sambotc]

Thanks for the advise, sorry forgot to reply sooner. I had a look on google and found some interesting info on phase converters but until I know what type they use I found myself a bit lost. I'll be honest, i've never touched 3 phase. I understand the basic prinicples of 3 phase, and looking at what this job may entail, I think i only need to supply a 3 phase supply to a large commercial boiler, so presume it will be fairly straight forward L1 L2 L3 & E connection? I think it is used for efficiency on a couple of large motors used in the appliance. I would think cable sizing etc would all be specified prior to install, although being 230v per phase is there any difference?

How do you go about testing via a phase convertor?

If there is any advise anyone could share with me on 3 phase used in this manner I would appreciate it.

Cheers, Sam

 

[Knobhead]

How do you go about testing via a phase convertor?

Disconnect it first before testing, otherwise did deep in your pockets for a new one. At least if it’s as you say 220V three phase it will only be a single stage converter.

Have fun with the set up. Don’t worry most work out the box with factory defaults.

The ones I hate are Leroy Sommer, a French sadist set up the menus for them!