VFD milling question

[Nick HulmeParticipant @nickhulme30114]

Posted by Emgee on 05/12/2016 12:31:36:

Searching VFD on the linked page provides 32 choices, not much help to the uninformed as there are more than one with electrical bias.

Emgee

IMHO It's good for people to have to think and do some legwork, I think we should all try to use, TLAs, acronyms and abbreviations wherever possible

HTH

Nick

[BikepeteParticipant @bikepete]

Posted by Alan Waddington 2 on 04/12/2016 18:31:40:

Slight update, it sprang to mind that i already have a VFD running my lathe, it's only 2.2 kw so wouldn't be any good for real work as the mill motor is 2.2 kw, but i figured it should run the spindle quite easily with no load.

…

I'm now shopping for a 4kw inverter to run the spindle motor

Sorry if I'm missing something but do you really need more than a 2.2 kW inverter to run a 2.2 kW motor? As far as I'm aware and in my experience, reasonably modern inverters will do what they say on the tin – no need to over-rate. Might be worth trying the 2.2 kW one on some 'real work' – I'd be surprised if it wasn't perfectly adequate.

There's also a much wider choice of single phase input VFDs in <= 2.2 kW than there is in higher power ratings.

[Howard LewisParticipant @howardlewis46836]

I thought that it was the peasants who were revolting.

Or did I mistakenly spell that with "as" instead of a "d"?

Howard

[Alan Waddington 2Participant @alanwaddington2]

Posted by Bikepete on 07/12/2016 08:57:56:

Sorry if I'm missing something but do you really need more than a 2.2 kW inverter to run a 2.2 kW motor? As far as I'm aware and in my experience, reasonably modern inverters will do what they say on the tin – no need to over-rate. Might be worth trying the 2.2 kW one on some 'real work' – I'd be surprised if it wasn't perfectly adequate.

There's also a much wider choice of single phase input VFDs in <= 2.2 kW than there is in higher power ratings.

I'm sure your probably right Pete, but as I had to buy one anyway, I thought there was no harm in having a bit of headroom. Especially as I've gone for a cheapo chinese jobbie, £130 delivered for a 4kw inverter.

i paid more than that for the 2.2 kw one, which was secondhand, although it is a good name brand.

[Mike PooleParticipant @mikepoole82104]

An inverter is not necessarily a Variable Frequency Drive (VFD). I was taught that is was only allowed to use abbreviations after the term had been used in full in an essay. Many technical books will have a glossary to expand on any abbreviation used. The inverter is only the output stage of a VFD. The AC is first rectified to provide a high voltage DC stage usually called the DC link then it is switched to give three phases at the desired frequency this is the inverter part usually implemented these days with Insulated Gate Bipolar Transistors (IGBT)

Mike

[MuzzerParticipant @muzzer]

Indeed, you'd struggle to run a 3-phase motor with one of these inverters.

Alan – if you are going to spend that sort of money you might as well buy a proper one. It will do a genuine 2.2kW without breaking into a sweat and won't pop when you try to use it. Why have cotton (or a pig's ear) when you can have silk?

Murray

[Alan Waddington 2Participant @alanwaddington2]

Posted by Muzzer on 07/12/2016 21:23:43:

 

Alan – if you are going to spend that sort of money you might as well buy a proper one. It will do a genuine 2.2kW without breaking into a sweat and won't pop when you try to use it. Why have cotton (or a pig's ear) when you can have silk?

Murray

Yeah, wish I'd known about that site before I ordered. A 4kw Yaskawa is only £190 too…….. Oh well too late now. To be fair my mate has been running a 2 post ramp from a chinese VFD for ages with no issues, so maybe it will be ok.

 

Edited By Alan Waddington 2 on 07/12/2016 21:49:41

[MuzzerParticipant @muzzer]

Oops, sorry about that. Being a Scottish-blooded Yorkshireman, I understand how this can cause a significant loss of sleep!

Note that the model I linked to is the J1000 series which operates in simple "constant VF" mode, whereas the V1000 models use sensorless vector control ie a bit more sophisticated. Worth the extra £20 in my mind but depends if you are working to a budget.

The V1000 technical documentation gives you an idea of the capabilities of these industrial drives.Pretty impressive stuff.

Murray

[Alan Waddington 2Participant @alanwaddington2]

Yup V1000 4kw £191…… **LINK**…….would have definitely stumped up the extra £60 to get that

[BikepeteParticipant @bikepete]

Note that the Inverter Supermarket prices don't include VAT (20%) or shipping (about a tenner IIRC). So £191 turns into more like £240 delivered…

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