Inverters? Talk to me.

[HollowpointParticipant @hollowpoint]

At some point I intend to purchase an inverter for my Boxford Lathe. Which is currently wired up with some home brew 3 phase thing which just doesn't cut the mustard. The problem is that I know practically nothing about electronics. I've been doing a bit of reading but I still have many questions.

How difficult are the inverter's to wire up and program?

Should an inverter be the same specs as your motor or be a bit bigger? ie 1hp motor 2hp inverter?

Can most or all inverters control speed and reverse from a remote pod?

Is there any brands to look out for? And any to avoid? (Anyone used invertek?)

[HollowpointParticipant @hollowpoint]

[Harry WilkesParticipant @harrywilkes58467]

Hi I installed a VFD and three phase motor on a Myford and have been pleased with it ever since.

Not to difficult to wire up some people get confused changing the motor to delta but with newer motors this is pretty straight forward

I would say HP of motor same for inverter

Most VFD's are fairly easy to wire for forward/ reverse jog and speed control all remotly.

What brand everyone will have their favorite I got my kit from Transwave Jag cub VDF but I stayed with a imperial motor as I did not want to both with new pulley, plenty of help and advice also from them as well.

One thing I can say is that if you get stuck there are some great guy's on this forum who will put you right !

H

[Michael BriggsParticipant @michaelbriggs82422]

Hello, there should be no need to under rate an inverter for lathe use. Generally you will find that the quick start guide part of the manual is a simple procedure to establish base settings. I have start, stop, direction and jog controls with a speed potentiometer, you will have to dig deeper in the manual to set up a jog control. Be mindful that you are dealing with potentially lethal voltages so if you are unsure seek professional advice. Regards, Michael.

Edited By Michael Briggs on 08/03/2016 22:26:12

[Alan Waddington 2Participant @alanwaddington2]

Have a word with Gavin Oseman 01684 574966, he sometimes advertises on Homeworkshop.org.uk. Bought the inverter for my Colchester from him, it came pre programmed and had a remote pendant wired up. Very reasonable price and he tends to sell quality name brand inverters.

Saying that, my pal bought a 5.5kw ebay special to run a two post ramp and it has worked faultlessly, although the manual/ instructions were a touch sketchy to say the least, and it took a bit of messing around to set up.

I

[Chris Evans 6Participant @chrisevans6]

I have a Chinese inverter on my Bridgeport mill. Over rated to motor size, it was sub £95 a couple of years ago but I would have struggled with the "Chinglish" instructions. A friend set it up with no trouble.

[HollowpointParticipant @hollowpoint]

OK that all sounds promising I've seen a few ready made remote pods for sale, are they all wired up the same and would these typically work with all inverters?

[duncan webster 1Participant @duncanwebster1]

I've now bought 3 from Newton Tesla. Very helpful chaps, helpline 7 days a week and in English!

[Nick_GParticipant @nick_g]

Posted by duncan webster on 08/03/2016 23:24:45:

I've now bought 3 from Newton Tesla.

.

Ditto.

Got 2 of their Mitsubushi ones.

If required they sell a controller pendant to go with them so all you would have to do it put a 240v supply to it and connect the 3 motor wires and it's earth. You may also need to alter 3 links in the terminal box.

Good UK company with backup should it be required.

Nick

Edited By Nick_G on 08/03/2016 23:48:19

[Thor 🇳🇴Participant @thor]

I installed an inverter and 3-phase motor from Transwave on my HBM 290 lathe, and I am very satisfied so far. The remote pod let me switch between forward and reverse, between jog and run, and using the pot.meter I can change the speed. I downloaded the manual and managed to program the inverter and connect the various leads without much problem.

Thor

[David JuppParticipant @davidjupp51506]

Posted by Hollowpoint on 08/03/2016 22:35:19:

OK that all sounds promising I've seen a few ready made remote pods for sale, are they all wired up the same and would these typically work with all inverters?

You can't assume that they are all wired the same. Even if they are equivalent, colour codes or labelling of wires may vary.

If unsure of your ability to work it out, buying inverter and remote from same source would be sensible. Perhaps as a minimum, download the manual in advance for any inverter you consider and check if you can follow it.

[Mike BondarczukParticipant @mikebondarczuk27171]

I have just very recently installed a Transwave inverter plus a remote dongle to my Myford Tri-Leva and all was exceedingly easy and the instructions are remarkably clear, with colour pictures to ensure correct wiring connections.

I have also just installed another Transwave converter for my 3 phase Hardinge and that was another easy operation.

The only comment I would add at this stage is for a suitable enclosure, B&Q currently have IP45 rated boxes which are a perfect fit for the inverter and ensure nice tidy and safe wiring and protection against swarf and cutting fluids, and at less than £10 it is a bargain and I believe that is is labelled a "garden outlet connection box" or something similar.

Another plus for Transwave is that if you do have any problems their technical support is superb, and I have no connection to Transwave apart from being an extremely satisfied repeat customer.

Mike

[Gray62Participant @gray62]

Another thumbs up for Transwave, I bought a motor/vfd/remote pendant package from them a couple of years ago.

Straightforward fit and works perfectly. I've used inverters from Teco, IMO and Omron in the past, none of which are difficult to wire up, the remote control side is all low voltage (24V dc).

Excellent support from Transwave, no hard sell just sound advice based on experience.

Some of the manuals can be a bit confusing as to how each parameter affects the inverter control and some inverters will require a control relay in the remote pendant as not all inverters will work directly with non-latching switches, but all fairly straightforward to do. I usually build my own remote pendants as I find the £60 -70 most suppliers charge a little steep.

[john fletcher 1Participant @johnfletcher1]

My friends have bought inverters via ebay for about £90 and non has had any problems. Some of the instruction take a bit of working out but, we got there in the end. I made the remote controls following the instruction, the components can be bought on ebay for a few pounds and the for the multi core cable we used some ex computer cable. It appear daunting but once you calm down its not difficult. Inverters seem to be rugged. Have a go I'm sure you will be pleasantly surprised.John

[Mark P.Participant @markp]

Has anyone used “the inverter supermarket”
Mark P.

[Neil WyattModerator @neilwyatt]

Story of my Jaguar Cub package from Transwave:

http://www.model-engineer.co.uk/news/article/3-phase-conversion-and-other-alternative-methods-of-powering-a-mini-lathe/18752

Neil.

[John RuddParticipant @johnrudd16576]

Posted by Hollowpoint on 08/03/2016 21:26:06:

Is there any brands to look out for? And any to avoid? (Anyone used invertek?)

I have an Invertek 1.5 kw vfd on my big lathe, SPG 2129 running a 1.5 kw motor…..no issues at all….

I have an Imo iDrive EDX 75 series vfd running a 3/4 hp motor on my Chester 9*20 lathe, a Teco Minicon series rated at 0.4 kw running my Ajax milling machine, and my Chester Eagle 30 mill is running a 1.1kw motor with a vfd…..

[Russ BParticipant @russb]

I have a couple of CL1500's (2HP/1.5KW) from Newton Tesla and I could be tempted to part with one of them

I have picked up a Mitsubishi inverter (the same as is fitted inside the CL1500's) which I will be mounting directly in the electrical control box, hiding inside a cupboard or just hanging on the side of the lathe stand (it's only a small thing).

The plan is to wire up appropriately to keep the "original" look. I never liked having the CL1500 hanging off the side of my setup. That said, the control panel they incorporate is absolutely brilliant.

I'm not yet sure if I want just a reverse/off/forward switch at 50hz or 60hz of if I wan't to take advantage of the variable frequency. I don't have a spindle speed read out – so when I'm using the variable speed on the mill and lathe I've got to use my optical rpm gadget to read the speed, otherwise I just don't know – its a bit of a step into the dark.

Edited By Russ B on 09/03/2016 09:16:34

[Chris Evans 6Participant @chrisevans6]

I still have the Chinglish instructions for my cheap inverter. I will find them and re read to see if they can be understood by average folk. I must admit to leaving the setting up to a friend but now I am looking to add more machinery I will be buying another Chinese inverter.

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Mark P. on 09/03/2016 08:45:32:
Has anyone used "the inverter supermarket"
Mark P.

Yes, I have bought inverters and motors from them. Good prices and fast delivery to me in France. Recommended.

Russell.

[Involute CurveParticipant @involutecurve]

Don't mean to hijack this thread, but it is related, I'm helping a mate build a spray booth, the extractor fan motor is rated as 3KW 220/415V and drives the fan via belts, we could do with slowing the motor on occasions i.e. after the actual spraying is over, then slow the motor to just keep a small airflow and stop all the heat being blown out of the room.
Most of the inverters I've seen are single phase in, we could wire the motor to run 220V 3 phase, and use a single phase inverter, however we do have a 3 phase supply already running the motor, I've seen some inverters listed as 380V!!.
What are the options with regards to using a VFD to slow this motor.

Thanks in advance

Shaun

[AjohnwParticipant @ajohnw51620]

Most people I am aware of who have converted a Boxford have fitted a bigger motor. Do look at fitting it carefully though.I fitted a 1HP to my ME10 and just about managed to get fixing holes on the motor mounting plates. I only looked at frame size which was just about ok. I didn't check that against where the mounting holes would need to be. Some of my fixing blots had to be high tensile M4 which shows how tight it is,

The reason for going bigger is so that the motor can be slowed down and still provide the torque that was available with a belt reduction to the same speed. There is a catch however – motor cooling limits how slowly they can be run and significantly loaded for any length of time.

What I did to get round that to a certain extent was to fit a 6 pole motor but that means to get up to the usual speed it has to be driven at 75Hz. The manufacturers are very coy about what they reckon can be done but in this case they indicated unofficially that they doubted if it would be a problem. This was Brooks. If something went wrong they would deny saying it. Anyway I set mine to drive from 40 to 80Hz which should be bomb proof. It's easy to put the back gear in if I need low speeds.

It's possible to find a TEK catalogue that shows what they think their motor inverter packages can do via graphs. There is another one that doesn't give this level of detail which usually pops up in searches. All makers are more or less the same really other than dedicated inverter drive motors which up the costs a lot. I think there was an interesting post recently concerning the UK TEK agent. Maybe you should read it.

What do I think now I have done it? Mixed feelings largely down to noise. They are loud. The random switching in my Mitsubishi inverter helps a hell of a lot but it's still a lot noisier than the original single phase motor. I understand something can be fitted between the motor and inverter to fix this but have never managed to tie it down.

If I look at it logically as the ME10 has a countershaft it's easy to change speed so why do it. The back gear also adds more flexibility. I did feel the need for a more powerful motor though. I managed to let a bit of the smoke out of the original one. That was an interesting experience. I noticed a bit of a smell so stopped. The smell got stronger and stronger and eventually some smoke appeared over a period of at least 15min. It takes a long time for the heat to work it's way through the motor and a extremely long time for it to cool down again. The heat came about by simply reaming a rather large hole with a so so reamer circa 1 1/2 dia – should have put the back gear in.

John

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[EmgeeParticipant @emgee]

Shaun

You can use a 3 phase 415V input VFD to replace the existing starter and leave your motor connections as they are, for convenience simply fit the speed pot close to the VFD unit.

Any electrical equipment installed within spray booths needs to be specially rated to prevent explosive vapours being ignited so any non rated VFD will have to be mounted in a safe area away from the booth.

Emgee

Edited By Emgee on 09/03/2016 13:46:24

[Russ BParticipant @russb]

Shaun/InvoluteCurve,

Inverters are not really inverters – they're VFD's (Variable Frequency Drives) (the inverter is the back end of the VFD, the transistors that take the DC current from the converter/capacitor bank and switch it back to a rough AC wave)

also could be called variable speed drives, adjustable speed drives adjustable frequency…. you get the point. If you looking for one cheap, its worth checking all these names online when searching the classifieds.

I believe you just want a variable frequency drive with 3ph in and 3ph out – these are often the cheapest second hand since they're more commonly used in industry and worth less to the general public – if you see a nice inverter going cheap, its probably becuase its 3PH in and/or its 415v.

Buff up on your ATEX ratings to get one with the correct internal/external explosive atmostphere rating (any ATEX is not good enough, it must be the correct zone1/2 ratings) – or cheaper still, put it inside and ATEX rated enclosure and use ATEX rated cable glands etc). I dont know if you can buy ATEX inverters due ti the nature of the job they do.

Edited By Russ B on 09/03/2016 13:56:51

[Michael BriggsParticipant @michaelbriggs82422]

Hello John,

The device to fit between the VFD and motor to reduce noise is a three phase choke, that should iron out some of the harmonics from the output. They are primarily installed to reduce leakage on long cable runs that can cause false tripping.

Increasing the PWM frequency can also reduce noise in the motor. I have Allen Bradley drives installed on three machines, the motors do not make any discernible drive related noise.

I remember past VFD installations where the motors rang with a pretty unpleasant noise. I don't think it is as much a problem with modern devices.

Michael

Edited By Michael Briggs on 09/03/2016 13:55:33

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