'Hacking' an inverter

I have recently bought a Schneider Altivar 61 on ebay, from a dealer 'Drives Direct'. It was advertised as being able to power a 3/4hp motor, single to three phase.

When it arrived I downloaded the instructions, which showed that the inverter was rated at 0.5hp with a single phase input. The higher power rating was for a 3 phase 240v input.

I questioned this, and was told that this drive had been 'uprated'. Having spoken to Schneider technical support they told me this was not possible.

This I reported back to the seller, who informed me (after some hassle, I must say) that he had reprogrammed the trip rating from half to 3/4hp, and this was a 'trade secret'.

The seller has attempted to cancel the transaction and refund my money, but I am concerned to know whether this practice is common and/or safe.

In the listing the item was described as new, and no mention was made of reprogramming it. He claims to have sold more than 60 of these to satisfied customers.

The datasheet for the exact model is here: http://www.datasheetlib.com/datasheet/778647/atv61h075m3_square-d.html

Any thoughts?

If hes changed the rated output from what you believed the original product should normally produce, then its miss-selling you, I'd get your money back and stay clear. Its not right for the customer, thanks for the heads up though.

Ps. This is a big no-no because when you buy a motor for use with an inverter, it's best to get an inverter that can handle 25%-50% more than your motors rated output so that it will operate well under sustained duty cycles. It will just keep overheating after more than maybe 30-40minutes usage. 

Michael W

Edited By Michael Walters on 07/03/2016 10:09:26

The dealer has probably got away with this because most motors do not run at full rated power all the time. Who, for example, has a lathe cutting at maximum metal removal rate 24 hours a day? I agree with Michael W. Always get a bigger inverter than the motor requires, it may be re-purposed or the motor replaced with a larger one.

Martin

There is also the possibility that the hardware could be totally identical to one with a larger output capability, but knobbled to a lower level by the firmware. It's often far easier to run one larger volume production line with the exact same bill of materials and just apply a different label and level of firmware before it exits the factory gates. Such an approach has become quite common in recent years with test equipment such as oscilloscopes.

Inverters I have bought have an overload capability well over their rated power. Sounds he has used some or all of that up. Not a good idea. As some one has suggested the rather large high quality and expensive capacitor these things use will be over rated.

Tell him to get ********* and send it back. If it was ebay it deserves a negative and why in the feedback. I had some dealings with who I think now is drivesdirect when he started up. I was impressed. He was helpful and thoughtful about what he sold. I contacted him later for a new manual - he wanted a silly amount of money for what he could just leave for downloading on the web.

There is a person on homeworkshop.org who regularly sells inverters and seems to have many happy customers. He's in Worcester. It might be worth contacting him.

Sounds like when people buy inverters now they had better check that the specs tie in with the seller's.

John

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Thanks very much guys for the opinions. My initial reaction was that I was being conned, but being unwilling to jump to conclusions I kept asking for more information about this 'uprating', and why it was not revealed in the listing. The thing I find interesting here is that this a not apparently a bunch of cowboys. He says:

<We have 30 years expertise in inverters from 0.1HP up to 1 Megawatt and not only do we sell these but we service and repair the whole range down to component level and we are Teco's UK service agents, we get asked by Teco and other inverter suppliers to give advanced technical support so when we supply an item we know what we are doing...>

In one of the latest messages (after I said I had spoken to Schneider's technical department) he says:

"These people at technical departments you seem to think know everything have to deal with a vast range of products and the knowledge of any specific range is limited and they can then only go by the information they had and in 99% of cases thats the manual you have, and reading that it says nothing about upgrading etc,
The makers want you to by an expensive new model at £250 so they will tell you it can not be upgraded and if you want to do that then thats fine,

Only the factory design engineers who like us understand every working area of the unit and also know the software inside out would know how to upgrade products BUT they would not tell you and likewise we would not tell you how its done but its out there in the market on all sorts of products, for example i drive an Audi Q7 and by going into the ECU, the computer that runs the engine i have reprogrammed it to give me an extra 100HP of power, the makers will not tell you that can be done and the technical department will tell you its not possible, we have here a range of IMO inverters, the i-drive 1.5KW unit is designed to run motors up to 2HP, you call IMO and tell them you want it to drive your 3HP motor and they will tell you to purchase a more powerful unit BUT send that same 2HP unit to us and in 5 mins it will be a 3HP unit !"

I am at a loss to understand why a company which has apparently a considerable business and track record should be doing this. It is extremely odd.

Roland

That, it seems, is what the dealer is suggesting.

.

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Drives an Audi: Says it all..................................

Some one who hasn't been involved in electronic just wouldn't understand why electronic components can appear to be well under rated. What he is basically doing is taking something that has been designed for continuous industrial use and removing some or all of the allowances that have been made for parts variations. Electronics bits and pieces vary even the same part numbers from the same manufacturer. In practice due to supply companies who build may at times buy the same part from more than one manufacturer and there will be variations. Industrial items like inverters will have been designed around worst case figures.

Industrial ratings of components are also often different. Taking a simple item there was a lot of 1/2 w resisters that couldn't be used for the product at work so we could help ourselves. Later I bought some 1/2w resistors and was gob smacked by how hot they got. In my terms these 1/2w resistors were barely 1/4w. T ransformers are another area where this happens, the max current rating of many is a joke. Active components for commercial use are often rated at 0 to 70C. Automotive -40 to +85C, military even more than that. Some people are inclined to think the only difference is the labelling. If only.

John

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I bought a 3HP IMO Jaguar inverter to drive a bandsaw , off him on ebay several years ago, it worked for a few days then went dead. I got no refund despite sending the item back .I wouldnt deal with him at all because if anything goes wrong he doesn`t really want to know .Thats my experience .

I got the impression that if you were only a private buyer and not spending thousands then you weren`t worth helping with the problem.

Edited By mark smith 20 on 07/03/2016 11:06:55

Hello All,

I have worked with inverters since they first appeared on the market, that probably encompasses a few thousand of them. The seller is wrong and should be avoided, you can run a motor with a slightly under rated inverter if it is lightly loaded but it is not good practice.

On the other hand I don't agree with comment from Michael Walters, the only time an inverter needs to be over rated is when it is used with equipment that requires a very high starting torque such as a mixing machine that has stopped mid cycle.

In my workshop I have a lathe, miller and bench drill, all inverter powered. They all generally start under no load so there is no need to de rate the drive, don't waste your money.

Michael

I think it's interesting, because i've run a 750 watt motor on a 750watt inverter on a lathe into a long piece of 1" square mild steel on a 1mm cut, on the leadscrew auto feed gear train and a tailstock centre and through coolant running, got about half way through it and the overload warning comes on. I've done the same thing with a 1.5kw inverter, motor no different and it doesnt complain. So duty cycle can be important.

Obviously i'm not the judge of what other people need to do, but i needed this to do that, so all i can say is buyer beware. I should add that i think my named counterpart has some good points, its true that it doesnt start under load and this new inverter was fan cooled rather than totally enclosed, so i could be wrong but it worked anyway.

Michael W

Edited By Michael Walters on 07/03/2016 12:40:22

My comment regarding under rating inverters should have included applications where there are very high torque requirements at times during the machine cycle.

Michael

Hello Michael,

Inverters should be able to run at 100% load 24/7. I would check the motor current, either you had a faulty inverter or you are overloading your motor, the latter will end in tears.

Michael

The first thing people should do with an inverter is enter the values on the motor plate into the firmware so in some ways the inverter rating doesn't matter other than some may only allow some minimum current to be entered. In other words it might not be possible to enter the correct values for a 1hp motor in a 2hp inverter.

On the inverter on my lathe overloads are handled in 2 ways. From memory the inverter itself is happy with a 50% overload but also models the thermal behaviour of the motor - that is a facility that has to be enabled. The 50% is built in and may have some limits applied. I was more worried about my motor burning out rather than the capabilities of the inverter. Again from memory the inverter will allow it's power rating to be dropped via setting by 1/4hp but no more. No idea why but it could be down to emissions.

I don't know what lathe or tooling or speed you are using Michael but my Taig / Peatol would take that cut - if it was square bar though it would shake it about a bit.

John

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I had good experience with Drives Direct, but probably 5 or more years ago. They have certainly been going a long time and have certainly sold a lot of inverters.

However, now, if I need an inverter, I take a risk on a second hand one from ebay. So far I'm up on the deal.

Maybe i've been a bit daft or something because i dont remember needing to enter current rating into my inverter, it only stipulates the frequency. I'm using an IMO idrive2 so maybe i've gotta flick back through that cryptic manual and see if i missed a setup step quite important and just willfully overlooked. perhaps i'm not getting what i should out of it because of my operational error.

Michael W

The IMO Jaguars can be uprated by 135% with F11.

Neil

Hacking equipment to operate outside of the design parameters will more than likely invalidate the 'CE' marking.

Simplistically, for EMC (electro magnetic compatibility) emissions tests, equipment is (or should, if done correctly) be tested in a worst-case condition which usually coincides with maximum supply current being drawn. I have no experience of testing inverters but, in my opinion, pushing them to operate beyond their design parameters will likely result in conducted and/or radiated emissions limits being exceeded.

Alan