4 post lift Running a 3 phase motor on single phase

[brachunky]

We will hopefully start fitting the lift at Auto Distraction H/Q some time this month and although I will play a lesser role in it's installation, I need to get the kit together to get things going.
As mentioned in a thread elsewhere, the lift is currently wired for 3 phase and this requires some electrical magic to power it from our available single phase. With limited funds, we will most likely have to go down the chinese type converter/inverter route commonly seen on on the likes of ebay. 
Am I correct in thinking something like this will do the job being about a third more in capacity than the motor it needs to power ? Whats the "variable frequency" all out?

www.ebay.co.uk/itm/404712282868

The motor in question:

[vitesseefi]

Um, probably.

You’ll need to arrange the links in the motor terminal box for 220v (delta) there’s likely a sticker in the lid showing it.

As for the inverter, the challenge will be getting enough current for the starting torque. Going up a size with te largest possible overload capacity is the way to go (2.2 or even 3kW for the 1.5 kW motor at least 150% overload). There’ll likely be some witchcraft involved in the inverter set up too but I reckon it should be possible to make it work.

[homersimpson]

In theory it can be done but you need to be careful and its likely that the inverter will need to be significantly oversized to cope with the startup current on the motor.

Note that the Machine Mart one specifically states that its not suitable for car hoists: www.machinemart.co.uk/p/pc-60-5-5hp-phase-converter/?da=1&TC=GS-010712795&gad_source=1&gclid=Cj0KCQiAy9msBhD0ARIsANbk0A8WhqhnAInFHNVTdHGg52mrdpHhPMG_ciDac6rLHNtXtP5mYBzOPuQaAtB4EALw_wcB&gclsrc=aw.ds

[homersimpson]

Just to add, as the motor is only 1.5kW can you not just change it for a single phase version? 1.5kW is only around 6.5A so not a huge load, even direct on line the in rush should be ok on a type C or D circuit breaker.

[brachunky]

Jan 4, 2024 19:48:14 GMT vitesseefi said:

Um, probably.

You’ll need to arrange the links in the motor terminal box for 220v (delta) there’s likely a sticker in the lid showing it.

As for the inverter, the challenge will be getting enough current for the starting torque. Going up a size with te largest possible overload capacity is the way to go (2.2 or even 3kW for the 1.5 kW motor at least 150% overload). There’ll likely be some witchcraft involved in the inverter set up too but I reckon it should be possible to make it work.

Point taken, There's a 4kw version which would be a safer bet. I watched a video of  a guy in the states using  one for a milling machine who explained the witchcraft of which you speak!

[brachunky]

Jan 5, 2024 0:09:45 GMT homersimpson said:

Just to add, as the motor is only 1.5kW can you not just change it for a single phase version? 1.5kW is only around 6.5A so not a huge load, even direct on line the in rush should be ok on a type C or D circuit breaker.

It's a pity the Clarke unit excludes car hoists as it would have been the least "intrusive". A motor change makes sense but I would need to swot up on mountings and shaft sizing etc. There is apparently, the matter that the 3phase motor would be matched to the pump so fitting a replacement single phase motor could require a pump change too. Something to look into as from my limited point of view, it's either a motor change or a suitably sized inverter. 

[homersimpson]

Jan 5, 2024 9:48:19 GMT brachunky said:

Jan 5, 2024 0:09:45 GMT homersimpson said:

Just to add, as the motor is only 1.5kW can you not just change it for a single phase version? 1.5kW is only around 6.5A so not a huge load, even direct on line the in rush should be ok on a type C or D circuit breaker.

It's a pity the Clarke unit excludes car hoists as it would have been the least "intrusive". A motor change makes sense but I would need to swot up on mountings and shaft sizing etc. There is apparently, the matter that the 3phase motor would be matched to the pump so fitting a replacement single phase motor could require a pump change too. Something to look into as from my limited point of view, it's either a motor change or a suitably sized inverter. 

I don't profess to be an expert on either motors or inverters but I would have thought that a 1.5kW motor single phase or three phase would have the same output, 1.5kW is very small in motor terms and if I were specifying one at work I wouldn't expect to use a three phase motor for something this small.

With the inverters i'm not exactly sure how they work but when we fitted one at work for a portable extractor fan (because it was a lot cheaper than installing a three phase supply because of the route and it was only temporary) we found that we had to alter the phases around because one phase had  no voltage on it when measured (not sure why), I recall the fan control system was wired across L1 and L2 and we had to alter it to L1 and L3, its all a long time ago but I remember it worked well when in use but of course a fan has a lot smaller load on than a hoist, especially at startup when the load is at its highest.

[93fxdl]

Perhaps give these people a call and ask for advice
www.singlephasemotor.co.uk/?gad_source=1
Sounds like they do what you're looking for
Ttfn Glenn

[Ritchie]

Following with interest, I recently picked up a cheap 4 post Bradbury that’s 3 phase, I only have a single phase supply.

[brachunky]

Jan 5, 2024 16:48:31 GMT 93fxdl said:

Perhaps give these people a call and ask for advice
www.singlephasemotor.co.uk/?gad_source=1
Sounds like they do what you're looking for
Ttfn Glenn

Thanks Glenn

[kevins]

On my 4 post lift I fitted a single phase motor, pump was fine but the contactor (basically a relay) needed changing to a 240V one. Motor was the same shaft and power rating but it was phsically much larger than the original so now sticks out the top of the case. I do need to change the trip in the garage to a type C though as sometimes it trips on the inrush current.

We also have inverters on a band saw and planer, they work a treat but took a bit of fiddling to set up.

[vitesseefi]

Looks like an ordinary IEC 90 frame motor with B5 flange. Can’t see if it has the usual IEC keyed shaft but seems probable.

When checking out the single phase option note that the need the capacitor start, capacitor run variety which have the better starting torque rating. These are not the cheaper ones. Shouldn’t be very much bigger, though they tend to have very high terminal boxes to accommodate the capacitors.

[jimi]

You should be able to get a single phase replacement motor for that, you will probably have to replace the contactor as well (depending on the coil voltage) and may need to alter the control wiring to suit single phase. Shouldn't be any need to change the pump if the replacement motor is the same hp, rpm and frame size. The link 93fxdl posted looks to be well worth a call 👍 I've done motor changes many times at work, both ways 3ph->single and single -> 3ph, not a fan of using a inverter to simulate 3ph from single phase.

[Ritchie]

Brachunky, did you manage to get any success with this?
I’ve had a look at mine, it’s a different brand of motor from yours, however the rest of the setup looks the same.

[brachunky]

Jan 21, 2024 12:21:46 GMT Ritchie said:

Brachunky, did you manage to get any success with this?
I’ve had a look at mine, it’s a different brand of motor from yours, however the rest of the setup looks the same.

Eyup! I went for the 4kw invertor/converter in the end which incidentally arrived yesterday. The ramp is partially fitted (going to hopefully complete this week) and then it's onto the lecky stuff.