Spindle 2?

[John S]

All sorts, some generic Taiwanese el cheapo ones, IMO's Telemechaniques, Yaskawa and Fuji.
Motor powers from 0.25 Hp up to 7.5 Hp

Technically horse power is horsepower regardless of single or three phase, what does alter is the amount of amps pulled to get this power.
However the 3 phase goes come out on top as getting 3 pulses per rev it doesn't bog down as much as a single phase motor with one pulse per rev when a load is applied.

They are smoother, less vibration and with a VFD the 3 phase can have speed control, something the single phase one can't have.

.

[Ross77]

They are smoother, less vibration and with a VFD the 3 phase can have speed control, something the single phase one can't have.

I thougt you can control the speed of a 1ph motor with a triac based controller. seen them for about £10

Do these only control the speed and therefore have reduced power as well?

Seen a couple of VFDs on ebay for £150. dose this seem about right?

[irving2008]

I thougt you can control the speed of a 1ph motor with a triac based controller. seen them for about £10

Do these only control the speed and therefore have reduced power as well?

Only if they are PM motors (permanent magnet). 1ph motors with AC field coils cannot be controlled this way as they are synchronous to the AC input frequency. PM motors are low-fractional HP output.

Seen a couple of VFDs on ebay for £150. dose this seem about right?

Thats about right for a sub-1kw (.5 - 1HP) VFD. You must match the VFD to the motor.

[John S]

Thats about right for a sub-1kw (.5 - 1HP) VFD. You must match the VFD to the motor.

Although with a modern inverter they can be bigger than the motor as you can set the max amps it's allowed to pull and so protect the motor.

.

[Ross77]

Thats about right for a sub-1kw (.5 - 1HP) VFD. You must match the VFD to the motor.

Nothing is ever simple eh! is it just the max curent that is the issue when matching it to the motor?

Looks like I will have to research this a bit more, know of any good sites

Does this look like a good VFD,
http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=230343452299

Is 1.5K enough for decent mill? what size are you running your mills?
Thanks

[Ross77]

I'm a bit of a slut with power and such...I bought a 3KW VFD for £175 from Drives Direct at Nottingham.....via ebay (steal a bid when no-ones looking)

Cheers Kip, you must have been lucky they are £300 BIN now.
Still I supose its better to get it right first time, as you only end up buying lots of bits that might do, and speding more in the process.

How practical is it to move from machine to machine?

Patience is the key!

Is that waiting for a cheap one or Knowlege?:heehee:

[John S]

A lot of people who use a VFD to power two machines fit a red 3 phase socket on a flying lead and use that to swap over.

If the machines are close some have a wall mounted socket and use two plugs, one per machine.

Big No No is NEVER unplug whilst running, OK to unplug whist plugged into mains and switch on but not running.

One thing to watch when sharing is the motor load in amps as these 'should' be set per motor.
Say you have a 2 Hp VFD and a 2 hp motor drawing 8 amps and a 1Hp drawing 4 amps. When you swap over you need to change the motor load parameter to match. Depending on the VFD there may be other functions to change as well.

.

[irving2008]

How practical is it to move from machine to machine?

One thing to watch for... unless you have a 3phase supply you need a VFD that does 1ph to 3ph conversion... these have a higher input current and surge than a 3ph input

A 1Kw VFD needs a 16A circuit so not practical to put it on a 13A plug. My VFD is screwed to the wall between the lathe and mill and both motors are wired to the VFD through a big (30A three pole) two way switch. The VFD has two sets of parameters stored, one for each motor.

My lathe setup is 1.5hp AEI (c1965) 3-phase with a Jaguar VXS-75 VFD courtesy of eBay (£75 the pair, bargain).

[Gary]

Three phase motors and single phase motors rated at the same power and speed will give the same torque and speed as each other. (Thus the same power)
Power is (Torque*Speed/9550) so if you reduce either speed or torque the power will reduce.
So if you have a 1KW motor rated at 3000 RPM and you reduce the speed to 1000 RPM, then the power will be 333W. (assuming the torque stays the same)
You can only control the speed of an AC induction motor by varying the frequency, and this is only with a three phase motor.
A three phase motor comes Star or Delta and motors under 7.5KW are normally 220V Delta and 380-415V Star; you can use a single phase inverter and connect the motor in delta to run it from a single phase supply.

[brandon_costa]

All sorts, some generic Taiwanese el cheapo ones, IMO's Telemechaniques, Yaskawa and Fuji.
Motor powers from 0.25 Hp up to 7.5 Hp

Technically horse power is horsepower regardless of single or three phase, what does alter is the amount of amps pulled to get this power.
However the 3 phase goes come out on top as getting 3 pulses per rev it doesn't bog down as much as a single phase motor with one pulse per rev when a load is applied.

They are smoother, less vibration and with a VFD the 3 phase can have speed control, something the single phase one can't have.

.

I'd also recommend Yaskawa & FUJI. I wouldn't recommend ABB to anybody.

Has anybody worked with Yaskawa's latest drive?

http://www.clrwtr.com/Yaskawa-A1000-Drives.htm