BIG HP VFDs (was talk to me about Rotary Ph Converters)

[Shox Dr]

(I thought I'd start a new thread, while OnTopic. It needs it's own thread)

I've now got an ever increasing number of 3ph gear. I was looking for 1x2hp for a Mill, and a 1hp for the tool grinder, along with the need to replace the inverter on the Lathe. That's a lot of cash. when you can buy 1 for less than 300quid.

I was looking on (you know where) last night, and there are BIG VFDs available now for little money.

With one of these units, you could power a whole workshop. Of course you can only run one machine at a time, but I'm the only one here so that's not a problem.

I've nothing that requires 10HP but a little overhead, would hopefully extend it's lifespan, with scope for bigger kit.

I am thinking, a distribution board with enough sockets (4) and a switchover to direct power
A control cable could also be run from each machine so as to keep interlocks, RUN/STOP etc. It would give you DC braking as well.


Im I not seeing something here, or is it a good Idea.

 

[AndyStobbs]

How would you wire it up though? Everything in parallel?

 

[DanielW]

How would you wire it up though? Everything in parallel?

Relays?

 

[wheresmejumper]

Do you know they are 400v fed?

 

[DanielW]

Do you know you can get 400v relays with a contact rating of 690v AC.

 

[Spark plug]

Would you reprogram the the drive for motor size etc every time you changeover?

 

[wheresmejumper]

Do you know you can get 400v relays with a contact rating of 690v AC.

I was asking the op

 

[DanielW]

I was asking the op

Sorry my mistake but I thought you was refering to my relay post,easily done if you don't quote someones post to let others know who you're refering to.

 

[Robotstar5]

The basic idea seems sound, you could switch between the 4 outlets using interlocked contactors so only one in use at a time. Looping the start, stop etc round the workshop should work. The only thing that may be an issue is setting the different parameters for each motor?

 

[daleyd]

If you get a decent make of drive (I'm not being snobby, the cheaper drives are great for what they do but I just don't think they'd have this facility) you can store different parameter sets and each relay could have a contact to a digital in on the drive to select the correct set.

Doubt you'd get that facility on a cheapy one but the big name ones would be able to handle this. (Used to use KEB ones with multi parameter sets, but Hitachi, Schneider, Siemens etc should all be similar)

 

[Shox Dr]

Would you reprogram the the drive for motor size etc every time you changeover?

Is it necessary? The motor will draw what it requires. Just set it the biggest motor your running

As for the relays I thought you can spec any voltage. So all the interlocks etc could be low voltage

Do you know they are 400v fed?

What are? If you mean the motors are 380v then yes they are.

Either way 220v 1ph>380v 3ph or 220v 1ph>220v 3ph, would just need to change the motor wiring over.

 

[Robotstar5]

As for the relays I thought you can spec any voltage. So all the interlocks etc could be low voltage

I'd use 24VDC for control voltage/contactors etc.

 

[HughF]

Plenty of cheap, big kw VFDs on ebay, sold as HVAC inverters... But, all those big ones are 3x415v in, 3x415v out... Including the 10hp ones for £240 ish quid...

They are purely a VFD, not a phase converter.

 

[wheresmejumper]

What are? If you mean the motors are 380v then yes they are.

Either way 220v 1ph>380v 3ph or 220v 1ph>220v 3ph,

I meant those vfds linked need 380 or 400v fed to them.a 220v 1ph to 380v 3ph 10hp is pricey. 220v 3ph is probably the cheapest

 

[wheresmejumper]

Sorry my mistake but I thought you was refering to my relay post,easily done if you don't quote someones post to let others know who you're refering to.

Sorry,rushed typing on fag break

 

[Shox Dr]

I'd use 24VDC for control voltage/contactors etc.

That's the way I was thinking

I meant those vfds linked need 380...

http://www.ebay.co.uk/itm/171670470975?euid=ec7a45c6b9284d37a9605fa08c73c051&cp=1