Spindle 2?

[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.

.

[Ross77]

Typical, being the cheap skate that I am I thought I could save a few quid with the CHR spindle controller and a £10 speed controller. But looks like Im back the VFD route! :sad:

Then again, Bill what was that step up transformer system? I know you can step up the voltage but how dose the 3 phase bit work?:confused:

[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).

[BillTodd]

Bill what was that step up transformer system? I know you can step up the voltage but how dose the 3 phase bit work?

It's simply that the higher voltage vfds tend to be cheaper on ebay than 240v ones.

A 1Kw VFD needs a 16A circuit so not practical to put it on a 13A plug.

Irving, my 1k5 vfd runs on a 13a plug albeit via a transformer.

[John S]

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).

The VSX-75 is a 1 Hp model inverter and takes 7.2 amps with single phase input.

The next one up in the range is the 150 or 1.5 Kw which will run a 2 Hp motor and that requires 14 amp.

The later updated VXSM's take 10 amp and 16 amps respectively

The cheaper Mini series takes 6 amps and 10 amps respectively.

.

[irving2008]

The VSX-75 is a 1 Hp model inverter and takes 7.2 amps with single phase input.

The next one up in the range is the 150 or 1.5 Kw which will run a 2 Hp motor and that requires 14 amp.

The later updated VXSM's take 10 amp and 16 amps respectively

The cheaper Mini series takes 6 amps and 10 amps respectively.

.

thanks for that info John.. my motor is rated on the plate as 1.5HP but seems to work OK on that VFD, it doesnt even get hot (I do have a small fan on the heatsink but it really doesnt need it)... maybe for the lathe its OK as its not running for any significant time and the load is minimal (I cant do big cuts its not that rigid). the motor I have for the mill is 1HP and a fairly recent one (<10y old). Not fitted yet as I need to make some brackets.

The manual for the VSX-75 says it needs to be on a supply with a 16A surge rating and it did used to trip the 10A MCB on start (not every time tho) which is why its now on a 20A MCB (although a 15A would probably be correct except I couldnt find one at the time). Maybe it would work on a 13A plugtop but I reckon there be a few replacement fuses needed from time to time.

Incidentally there some useful info here on cable and MCB selection which shows, for example, that the 1.5mm 4 core cable sold by B&Q as central heating control cable is fine for a 1HP 3phase motor wiring up to 15m (not that you'd want to run that far anyway) - my VFD manual talks about 4mm cable (which is impossible to buy in short lengths!)