inverter 4kw

[aidank]

Im in need of a 4kw inverter, convert regular 240V to 3phase. I want to power a 4kw motor driving a vacuum pump, and connect a vacuum sensor (4-20mamp) I guess to control the lot.

I guess it will be 240V single phase to 240V 3 phase inverter rather than 240V single phase to 400V 3 phase.

Are these cheap chinese inverters any good or best to avoid.

 

[6ply]

Im in need of a 4kw inverter, convert regular 240V to 3phase. I want to power a 4kw motor driving a vacuum pump, and connect a vacuum sensor (4-20mamp) I guess to control the lot.

I guess it will be 240V single phase to 240V 3 phase inverter rather than 240V single phase to 400V 3 phase.

Are these cheap chinese inverters any good or best to avoid.

I have several "good quality" WEG VFD units. They work well. Only one has failed, probably due to my abuse.

I have owned 2 cheap Chinese units. One failed, reason unknown. But it cost only £25. I am currently using a 240 in 380 out unit on my drill. It works well and is easy to configure. It hasn't failed yet.

 

[Agroshield]

What lets them down is the quality of the documentation. So download the manual of any prospective purchase beforehand and see if you can understand what parameters you would need to set and where to poke the wires to achieve your desired control scheme, particularly as you want to use the current to control rather than a traditional pot and voltage divider.

It is generally said to treat Chinese horsepowers as optimistic, and as you are seeking something near the top of what is reasonable on a single phase input, that might be troublesome.

What sort of single phase supply do you have? Trying to achieve that power at the end of 50m of 1.5mm^2 extension lead may not be practical.

 

[Ace Paul]

If any use

Phase Converters - Machine Mart

www.machinemart.co.uk

 

[aidank]

What lets them down is the quality of the documentation. So download the manual of any prospective purchase beforehand and see if you can understand what parameters you would need to set and where to poke the wires to achieve your desired control scheme, particularly as you want to use the current to control rather than a traditional pot and voltage divider.

It is generally said to treat Chinese horsepowers as optimistic, and as you are seeking something near the top of what is reasonable on a single phase input, that might be troublesome.

What sort of single phase supply do you have? Trying to achieve that power at the end of 50m of 1.5mm^2 extension lead may not be practical.

its a 4kw single phase motor powering it at the min, and its only 10ft from mains fuse box, newly wired 2 years ago so should be ok on power supply.

 

[aidank]

ill need to purchase a motor, same frame size as i already have, is it 240V or 380V 3 phase i should be purchasing.

 

[Agroshield]

...is it 240V or 380V 3 phase I should be purchasing.

If your VFD is putting out 230v three phase, you need a motor that accepts 230v three phase as input.

These people have a good reputation:

https://inverterdrive.com/

If I list all 4kW motors they sell, I see 105 items. If you filter those by 230v three phase, you see 14 items (which is really 8).

4kW seems to be the power lever at which 400/690v motors become available and one of those would limit your options so is probably not such a good choice. What I am saying is do not just take 'dual voltage' written in a specification as automatically being suitable. Check the specifics of which two voltages the motor accepts.

 

[Gareth J]

Variable speed vacuum pump? Speak to dairy suppliers and get them to price up what you want. They'll do it all the time so will be able to recommend/supply vacuum sensors that will talk to an inverter.

Currently part funding grant available if it is for a dairy farm.

 

[aidank]

Variable speed vacuum pump? Speak to dairy suppliers and get them to price up what you want. They'll do it all the time so will be able to recommend/supply vacuum sensors that will talk to an inverter.

Currently part funding grant available if it is for a dairy farm.

yes, got the response "we can supply you a complete new system for 4.5k probably more, not interested in any smaller retrofits"

 

[MetalMonkey]

You will want a VFD with an analogue input that supports 4-20ma.

If you are purchasing a new motor then you can go for one that supports 230/400v (most will now) and configure it depending on if you get a 230v or 400v VFD.
If you are reusing your existing motor, then obviously you will need to check and see if your motor can run in delta (230) in which case you can get a 230v VFD, otherwise you will need one with a 400v output.
The only thing with using the old one might be the insulation class won't be up for long term use on a VFD.

Perhaps speak to somewhere like inverterdrive supermarket for advice on a model that suits your requirement, they also do motor & vfd packages.

Depends a lot on if it is something for home or business, and if it is mission critical.

 

[Agroshield]

If you are reusing your existing motor...

Please read post #5.

 

[Gareth J]

yes, got the response "we can supply you a complete new system for 4.5k probably more, not interested in any smaller retrofits"

I'll send you a few details on ours later in the week.

You should be eligible for a grant, if it's available on this round, even if you DIY it.

 

[Gareth J]

Quite hard to get the sensor in focus.

They recommend using shielded cable everywhere because of risks of interference with RFID stuff.

 

[aidank]

Quite hard to get the sensor in focus.

They recommend using shielded cable everywhere because of risks of interference with RFID stuff.

Is that a Dairymaster machine you have

 

[Gareth J]

Is that a Dairymaster machine you have

The VFD setup? No idea, supplied by a GEA dealer, so possibly their bits. Parlour is an aging fullwood.

A note regarding the sensor; it's located between the parlour and vacuum reservoir, quite a way from the vac pump.

I would say that it should be reasonably straightforward to DIY this setup, the hardest bit (for me) would probably be organising the settings on the inverter, which may have various control parameters set to suit vacuum requirements. And possibly even some that get customised to suit individual sites. Some vfd boxes have settings menus that are massive and learning what to change and why could take ages.

If you've only got the one pump/motor, might be worth considering leaving the existing setup as it and putting in all new. Will give redundancy and time to organise the new one

 

[aidank]

The VFD setup? No idea, supplied by a GEA dealer, so possibly their bits. Parlour is an aging fullwood.

A note regarding the sensor; it's located between the parlour and vacuum reservoir, quite a way from the vac pump.

I would say that it should be reasonably straightforward to DIY this setup, the hardest bit (for me) would probably be organising the settings on the inverter, which may have various control parameters set to suit vacuum requirements. And possibly even some that get customised to suit individual sites. Some vfd boxes have settings menus that are massive and learning what to change and why could take ages.

If you've only got the one pump/motor, might be worth considering leaving the existing setup as it and putting in all new. Will give redundancy and time to organise the new one

dairymaster use Invertek inverters for their Vari Vac.

How many units are you running with that system. Does your system have a vacuum reserve tank installed somewhere near the vacuum pump.

 

[Gareth J]

On a 14/28 swing over. There is a ~100-150l reservoir between pump and plant, I'm not sure how essential that is though. Runs the parlour fine but is on the limit for washing out.