Inverter with motor needed

I am looking for a Inverter with motor package for my 3/4 hp lathe, can anyone recommenced a supplier for this. I have sent a message to Newton Tesala which has advertised in Model Engineering magazine but will not reply to my questions that I need before I purchase one of there packages.

You could try Drives Direct based in Nottingham.

I've had motor/vfd packages from Dave without any issue.

Power Capacitors are first class, got all me invertors and motors through them. Used to be agents for Eurotherm drives. They are now made by Parker SSD. Me oldest Eurotherm 650 drive is 15 / 16 years old now and never one single issue in that time. WEG are also first class VFD's .

cheers.

I have not purchased anything from them but they had a trade stand at Midlands MEX a week or so ago. Had a chat with Alan Moss the boss who was very friendly and gave me lots of advice.

Converter King Ltd.

01283 762124

www.converter-king.co.uk

Transwave, sponsors on here are also extremely helpful.

Rik

Edited By Rik Shaw on 20/10/2016 14:27:02

Edited By Rik Shaw on 20/10/2016 14:35:28

Try

Gavin Oseman
Malvern
WR14
UK
01684 574966
[email protected]

.

I have had good dealings with this company on a few occasions, so cannot understand why they have not replied.? - Maybe something as simple as their 'spam filter' getting over enthusiastic for some reason. (they do that sometimes for no good reason)

Try the tried and trusted old fashioned way and give them a phone call.

I have 2 Mitsubushi drives from them and rate the product highly.

Nick

Transwave part of Power Capacitors. Top notch. Robert, the Eurotherm 650 series of the correct rating will suit your motor. I can't praise these drives high enough Eurotherm, WEG, Siemens. Never a glitch in all the years. i've used them. I have no experience of any other makes.

I've dealt with Inverter Drive Supermarket in Chipping Camden. They are both knowledgeable and helpful.

Just a suggestion but why not ebay?

I have 3 inverter drives , all new boxed ,fitted to 2 lathes and most recently a mill. Previous to that i had no experience of inverter drives.

All three motors were off ebay as well and were brand new .

My smallest lathe a pultra ,cost me £70 for the Brookes motor and Mitsubishi inverter.

The Southbend ,cost £130 for a Brookes 3/4 HP and a Siemens 440 inverter.

My latest purchase a mill ,i fitted with a 2 HP GE Electric washdown motor and Toshiba inverter cost £280

No complaints how any of the motors or drives are working and for 3 machines £480 is hard to beat.

Edited By mark smith 20 on 20/10/2016 19:24:14

Just a word of caution about inverters. If you have a 30ma RCD protecting your house and it supplies your workshop then you can have a problem if the inverter has a built in filter. I had to exchange one inverter for a filterless one on my lathe because of this problem. As far as I am aware the only problem to the mains supply is that the wifi router won't work if the lathe is actually running.

I did not have this problem with the Newton Tesla system I bought for my mill (don't know what's inside the steel box) but I did with IMO inverter that I got from Transwave. They were very helpful and swapped it out for a (slightly) more expensive Jaguar which is filterless.

HTH,

Rod

I'll add to your comments if I may Roderick.

​Newton Tesla told me some while ago that inverters require a small but measurable leakage to earth (approximately 10 mA ) to function correctly; without it the motors sound metallic.

​At the time of asking, we were still operating with tower block computer systems that had no possibility of saving work in the event of a power shutdown from the earth leakage trip. The house also supplied power to pond pumps in the garden that are notoriously 'lossy' things. Any further sources of leakage were quite likely to trip out the house supply and I carried on without making the change.

​Since that time, the workshop supply has been changed to one through a new dedicated earth leakage trip with it's own reference earth rod, completely isolated to the one that the house trip is referenced back to and the problem no longer exists. Lack of funds is the reason now for not taking advantage of that change!

​Brian

Hi Rod can you expand on this RCD, problem.

I have a consumer unit in the workshop fed from the house via armoured cable. The consumer unit in the workshop came with a on /off power mcb? type switch which i changed to a 30ma RCD switch years ago.

The only problem ive had with the rcd in the workshop was occasionally when i used one of those yellow 110v site transformers that i plugged into a socket fed from the workshop consumer unit. The RCD occasionally trips.

I have a recent problem when i wired my new inverter in for the mill via SY cable. I grounded the metal sheathing and the earth core at all points between the consumer unit and the motor. I fitted a rotary isolator between the consumer unit 20amp mccb and the inverter to cut power to the inverter.

Now the mill works fine but when i switch off the isolator switch the RCD trips. Any idea why.

The inverter does apparently have an in built filter of some sort described as a high attenuation emi filter  but i dont know about these things.

this is the inverter drive, **LINK**

Any suggestions?

Thanks

Edited By mark smith 20 on 21/10/2016 18:47:32

Edited By mark smith 20 on 21/10/2016 18:51:08

"I have a consumer unit in the workshop fed from the house via armoured cable. The consumer unit in the workshop came with a on /off power mcb? type switch which i changed to a 30ma RCD switch years ago."

That part in the above post i think should read changed to a ELCB,this is what i fitted in the consumer unit.

Edited By mark smith 20 on 21/10/2016 19:23:12

Nor me I'm afraid - I'm just a victim

My understanding is that some inverters have an emi (electro magnetic interference) filter built in. Apparently this works by letting the em spikes leak to earth and this can trip the RCD. The IMO inverter I bought had one and this constantly tripped the house protection. The replacement Jaguar inverter has no built in filter so, presumably, to comply with emi regs, a separate filter should be used.

I read somewhere that the filter leakage is of the order of 20mA so this can add to some small leakage elsewhere to create an intermittent trip. In my case though, as soon as I operated the inverter it tripped the RCD

And that, I'm afraid, is the sum of all my knowledge about these things. Any future inverter purchase in my workshop will be filter free.

Cheers,

Rod

Inverter drives are certainly not easy to understand once you get past the basic stuff.

My manual says you can reduce the PWM carrier frequency down to a minimum of 2KHZ which can stop ELCB `s from misbehaving . But also says you can get more motor noise. I`ll have to figure out how to reduce that and see if anything happens???

The manual also says you can use interference proof ELCB`s ,and then you can increase the PWM carrier frequency?

What i dont understand is why its tripping when i turn the isolator to the off position.

Thanks

Edited By mark smith 20 on 21/10/2016 19:43:26

Going back to the original query, it's not clear if you are looking for a generic motor and inverter bundle, or one of Newton Tesla's "pre wired" systems.

As various people have said, there are plenty of alternative suppliers for motors and inverters in general (for you to mount and connect up yourself, generally), and also options like Ebay, etc. - but as a nicely pre-packaged, bolt on option the Newton Tesla systems are hard to beat IMO. Should also be reliable - I had one on a mill for over a decade with no problems. The (metal cased) control panel is well laid out, the motor just plugs into it via a chunky connector, and it all 'just works'.

You can definitely get an inverter drive cheaper (and really, wiring them up etc. is easy enough) but the Newton Tesla system is a very tidy package and might be ideal for someone who doesn't want to mess with electrics.

Second the suggestion to give them a phone call in case emails aren't getting through.

Edited By Bikepete on 21/10/2016 19:41:05

A couple of points regarding problems that some invertor users have highlighted in this thread:

1. All invertors will produce an amount of earth leakage when used.

2. Earth Leakage is "cumulative" , your household electricity system may already be producing some leakage but below the 30ma trip level, adding an invertor may push it "over the edge" and trip your supply .

3. The most common items in your house that can be producing earth leakage are cookers, kettles and water heaters, devices with older brush equipped motors (washing machines) that have gone through a couple of sets of brushes also tend to have a bit of leakage - if you are having problems with your inverter tripping the supply try switching off these devices - a bit of detective work can sometimes reveal a "leaky" device .

4.When fitting an invertor drive the cable between the invertor and the motor should be a screened type. The screen is there to prevent interference and should be earthed at one point only.

5. A 110 volt transformer is unlikely to produce earth leakage but it can suffer from saturation, depending on a few different factors, when it is switched on it can trip the circuit breaker, this is based on a current overload and not earth leakage.

Hope this helps with a few peoples experiences

Martin

Thanks Martin, your point four, do you mean as in a foiled cable or does SY cable count as a screened cable.

Also by earthed at one point ,do you mean only one end of the screen is connected to an earth point. Ive heard this before and there seems to be people saying earth both ends and others saying one end only. Its highly confusing for a non electrical person to follow.

Martin's advice that earth leakage is cumulative just woke me up.

These days the average house is likely to have a lot of devices fitted with EMI filters plugged into the mains more or less permanently. TV sets, computers, radios, routers, white goods, heaters, air-con, telephone answering machines, video recorders, hifi systems, lighting etc etc. Together that little lot could be leaking enough to put an RCD close to the edge.

It would be useful to know. Can anyone suggest a safe way of measuring earth current leakage at the consumer unit? (I think simply cutting the earth cable to insert an AC ammeter would be unwise!)

Dave

I'm trying to understand this. Not denying that / if it works but an RCD doesn't have an earth connection - it simply measures the difference between the total currents in the L and N wires on the basis that the difference current must be flowing through another route ie back directly to the common neutral-ground point through ground rather than via the N wire.

I think the solution is to install a separate consumer unit in the workshop, powered by a non-RCD connection from the main panel. Any RCD within the workshop consumer unit will then be unaffected by leakage on the house circuits and vice versa. If there is a significant problem with leakage from individual machines, they could be individually protected by using an RCBO (earth leakage detector with overcurrent protection) for each troublesome machine. Each RCBO would be connected upstream of the RCD.

As far as I recall, an ELCB (earth leakage circuit breaker) or SELCB (sensitive ELCB) is just an old fashioned name for an RCD (residual current device). The Mercans and Canadians call them GFI or GFCI (ground fault circuit interrupter).

Inverters don't need leakage current to work. If they behave / sound differently when fitted with an EMC filter, I'd suspect something a little bit odd / questionable with the design. There are limits to earth leakage for portable equipment but of course VFDs are generally hard wired and/or installed in a system where that restriction doesn't apply. Consequently, there are any number of different EMC filters available according to the specific needs. 20mA would be excessive for anything remotely portable eg fitted with a 13A plug. The normal limits are 3.5mA for Class 1 equipment (ie equipment fitted with a protective ground connection).

Earth leakage is normally tested with an RMS measuring DVM in the ground connection. You could do this yourself but if it blew up when you were doing so, you might bugger your meter and get a nice belt off it if you are touching it at the time. No harm in doing it if you are careful to replace the connection securely afterwards.

Murray

Edited By Muzzer on 21/10/2016 21:53:41