Thread: 3 phase inverter

I believe the standard 3ph motor is 1/2HP.

I was looking for an answer to the same question last week. I considered a VFD so that I could keep the 3-phase motor, but it didn’t look like it was going to be compatible. I decided to go single phase, and found a new reversible 1/2Hp with the same shaft size and mounting plate for $160.

I have a current price list for RPC's in front of me.

Smallest unit will run up to 3hp and plug into a 10amp powerpoint.

Price..... a mere $2300.00


Cheers, Ken

It looks like a no brainer!
$2000+ or $200 or so it looks like a new motor
I also rang a mate of mine who can't get 3 phase where he lives and he said it cost him $2500 for his inverter
I got a quote on 3 phase to my shed a couple of years ago and it was $7500

So single phase it is!

1. If the motor is dual voltage you can get a 240v vfd cheaply from the US. This will give you obviously variable speed as well as reverse easily. Acceleration ramp up time is a controlable variable too, great for threaded spindle noses. Less than $300 AUD. You can get the same thing here of course, at twice the price +

2. RPC's can be made for less than $200 if you are resourceful and good at scrounging. Plenty of online information on how to make one.

3. Single phase is easier than the above. Does your motor quote mention a reversible motor?

A seller on eBay sells Crompton Greaves reversible motors, 3/4HP, just perfect for the Hercus.

I bought one for mine, but as yet haven't hooked it up yet. Price $160 plus del. It's made in India, but the quality is first class.

Much cheaper than any alternative.

Ken

Hi guys, I recently installed a 3hp 3ph mill in my shop with a static phase converter (240v single ph)and it works great! cost about $200 CAD. Might be a solution for some of you guys too.
al

Hi boilermaker1,
There are several ways to acheive what you are after. If your existing motor is wound with a Delta connection then you can fit a single Phase VFD, this will give you the ability to control the speed of the motor via a 10K Pot and use your existing Lathe controls to feed into the VFD for Forward, Stop and Reverse.Cost of VFD's varies but are getting cheaper and you can look at second hand units also. Look at the existing Motor name plate to get details for sizing.
Other than that you can look at Static Phase Convertors which are popular in the US or as you have suggested look at a Single Phase Motor. I suggest if you are looking at a Single Phase Motor go up in size e.g. kW as a Single Phase Motor dosn't have the Torque of a Three Phase Motor.

Regards,
Keith.

Hi Guys, Ive got a 3ph Hercus in a 240 v house. Ended up buying a bigger chinese lathe 12 x 36.Now contemplating converting the Hercus to 240 v.then deciding which lathe to keep and which to sell.
What is the user's name on ebay that sells the 240 v motors? All help much appreciated.

Regards Jim

I've been looking at some VFD specifications and find it very confusing. A lot of them say they put out 240V 3phase. Does anyone know if that means 240V per phase, i.e. 415V total or does it mean 140V per phase for a total of 240V?

Originally Posted by blackfrancis

I've been looking at some VFD specifications and find it very confusing. A lot of them say they put out 240V 3phase. Does anyone know if that means 240V per phase, i.e. 415V total or does it mean 140V per phase for a total of 240V?

It means 240V phase to phase, not 415V phase to phase. If your motor is setup as 415V Y, then there is a chance it can be setup as 240V delta and run off a 240V 3 phase VFD.

Thanks Vernon. So a standard delta wound 3 phase motor should be compatible with a 240V 3 phase VFD?

Originally Posted by blackfrancis

Thanks Vernon. So a standard delta wound 3 phase motor should be compatible with a 240V 3 phase VFD?

Possibly. If the motor is a 415V Y motor and can be rewired as delta, then yes. If the motor is a 415V delta, then no.

was a guy selling vs inverters on ebay cost around 200$ work well they are chinese . cheers bob

Thanks Vernon and Bob