3 phase inverter ?

makeitfit · 09-04-2016, 21:34

Hi learned ones who do elektrickery magic .
I need help working out what 3 phase inverter I need for my 4 post lift. We've only got ordinary 240 in the barn.
I've seen many online but came to realise I don't know what to get ?

This the label on the motor

rustic · 09-04-2016, 22:18

For most 3 phase motors of a particular frame size, there could be a single phase equivilent, but that is quite a big motor.

Another alternative, is a motor gen set, 240 volt single phase motor driving a three phase generator/ alternator.

For an inverter, you would need quite a powerful one to drive an inductive load of an electric motor. I would guess Rick would offer some advice on that.

solarman216 · 09-04-2016, 23:04

The plate says 220 delta 380-420 star so I am guessing it could be converted, but may well be wrong on that, but in any event it is not a large motor at 1500 watts so you can use any 230v motor at 2850 revs at 1500 watts, forget inverters for this they are a no go, you could use a phase converter but cost will be much more than a new motor at 230v, Rick

solarman216 · 09-04-2016, 23:30

My two post lift runs on 13 amp plug no problem all all and lifts 3.5 tonnes, Rick

glanrichbex · 09-04-2016, 23:43

Quote:

Originally Posted by solarman216

My two post lift runs on 13 amp plug no problem all all and lifts 3.5 tonnes, Rick

No doubt - but every time for that split second your starting it, your chipping a little bit at a time out of your main fuse, and one day it will be the straw that breaks the camels back. It's not good for the motor windings or mechanical components of an induction motor to start direct on line due to the load current and the sheer mechanical shock. It's always better to soft start a motor rather than presenting a short circuit.

makeitfit · 10-04-2016, 00:03

I wish I hadn't had the last wine . Not following it all sorry guys.
The lift is a Bradbury 3 tonne 4 poster and has this motor that drives a hydraulic pump. As far as I can tell it drives up and gravity down.
Is this kind of thing any good ?
http://www.ebay.co.uk/itm/1-5kw-2-HP...UAAOSwLVZVkoWg

glanrichbex · 09-04-2016, 23:28

There are a few conciderations

Is this motor required to run in both directions? In three phase it is done by swapping two of the phases. In single phase it's a bit more difficult.... but it can be done.

or

Does this motor run a hydraulic pump? this only requires it to run in one direction.

Is this motor required to start under load?

It would probably need to be a 4 pole single phase induction motor. When we look at a single phase motor, it is a really a three phase motor but it uses capacitors to derive the other two phases by utilising the phase shift phenomena of a capacitor.

The problem with this method is that it is not very efficient compared to a three phase motor. The power factor is only 0.7 e.g a 4KW single phase induction motor actually consumes 5.6KW

They also do not like starting under load, it may run all day at it's maximum load rating but getting it there is another problem.

When a motor starts, it can draw up to 6 times its running current until it gets up to speed. This will eventually knock out your main fuse which will take some explaining to your electricity provider.

To start a single phase motor successfully you need a softstart unit, like a Fairchild HFE2. This will analyse the current drawn by the motor and limit the voltage in sympathy to the rotation speed and dramatically reduce the start up current .

There doesn't seem to be many manufactures making soft start units for single phase motors above 3KW.

The other alternative is an inverter starter, this means you do not have to change your motor, it's a box which goes between the supply and motor. It's more expensive than a soft starter but by the time you've changed the motor and bought a soft starter, you would probably find it's cheaper to buy just the inverter.

09-04-2016, 21:34	#1
makeitfit Senior Member Join Date: Apr 2008 Location: on the beach WEST WALES Vehicle: Maverick TDi BLACK mmm Posts: 15,136	3 phase inverter ? Hi learned ones who do elektrickery magic . I need help working out what 3 phase inverter I need for my 4 post lift. We've only got ordinary 240 in the barn. I've seen many online but came to realise I don't know what to get ? This the label on the motor

09-04-2016, 22:18	#2
rustic Senior Member Join Date: Feb 2007 Location: Staffordshire Vehicle: Maverick Mk I 2.7 TD LWB Posts: 7,825	For most 3 phase motors of a particular frame size, there could be a single phase equivilent, but that is quite a big motor. Another alternative, is a motor gen set, 240 volt single phase motor driving a three phase generator/ alternator. For an inverter, you would need quite a powerful one to drive an inductive load of an electric motor. I would guess Rick would offer some advice on that. __________________ Ford Maverick GLX 1995 2.7TD LWB in illusion silver, 98k miles. Owned since new, for 22 years. Best car I have ever owned. Just wish I could drive it more.

09-04-2016, 23:04	#3
solarman216 Off road maniac Join Date: Dec 2009 Location: Bexhill on Sea Vehicle: Y60 Patrol Me, 3 ltr Mrs Posts: 17,431	The plate says 220 delta 380-420 star so I am guessing it could be converted, but may well be wrong on that, but in any event it is not a large motor at 1500 watts so you can use any 230v motor at 2850 revs at 1500 watts, forget inverters for this they are a no go, you could use a phase converter but cost will be much more than a new motor at 230v, Rick __________________ Ex banger racer now off road maniac Lokka on the front with manual hubs Diff lock on rear 3 inch SS straight through exhaust Manly winch bumper with 13000 lb winch 10 spike ground anchor, with multiple straps and blocks Super strong body cills capped with scaffold pole 20% stronger springs all round aggressive off road tyres on wheels so just swap. Aim to get stuck and be completely self sufficient in extraction, love getting muddy, 2ft deep is good but rare.

09-04-2016, 23:30	#4
solarman216 Off road maniac Join Date: Dec 2009 Location: Bexhill on Sea Vehicle: Y60 Patrol Me, 3 ltr Mrs Posts: 17,431	My two post lift runs on 13 amp plug no problem all all and lifts 3.5 tonnes, Rick __________________ Ex banger racer now off road maniac Lokka on the front with manual hubs Diff lock on rear 3 inch SS straight through exhaust Manly winch bumper with 13000 lb winch 10 spike ground anchor, with multiple straps and blocks Super strong body cills capped with scaffold pole 20% stronger springs all round aggressive off road tyres on wheels so just swap. Aim to get stuck and be completely self sufficient in extraction, love getting muddy, 2ft deep is good but rare.

10-04-2016, 00:03	#6
makeitfit Senior Member Join Date: Apr 2008 Location: on the beach WEST WALES Vehicle: Maverick TDi BLACK mmm Posts: 15,136	I wish I hadn't had the last wine . Not following it all sorry guys. The lift is a Bradbury 3 tonne 4 poster and has this motor that drives a hydraulic pump. As far as I can tell it drives up and gravity down. Is this kind of thing any good ? http://www.ebay.co.uk/itm/1-5kw-2-HP...UAAOSwLVZVkoWg

09-04-2016, 23:28	#7
glanrichbex Senior Member Join Date: Apr 2012 Location: wales Vehicle: Terrano R20/D4 Posts: 442	There are a few conciderations Is this motor required to run in both directions? In three phase it is done by swapping two of the phases. In single phase it's a bit more difficult.... but it can be done. or Does this motor run a hydraulic pump? this only requires it to run in one direction. Is this motor required to start under load? It would probably need to be a 4 pole single phase induction motor. When we look at a single phase motor, it is a really a three phase motor but it uses capacitors to derive the other two phases by utilising the phase shift phenomena of a capacitor. The problem with this method is that it is not very efficient compared to a three phase motor. The power factor is only 0.7 e.g a 4KW single phase induction motor actually consumes 5.6KW They also do not like starting under load, it may run all day at it's maximum load rating but getting it there is another problem. When a motor starts, it can draw up to 6 times its running current until it gets up to speed. This will eventually knock out your main fuse which will take some explaining to your electricity provider. To start a single phase motor successfully you need a softstart unit, like a Fairchild HFE2. This will analyse the current drawn by the motor and limit the voltage in sympathy to the rotation speed and dramatically reduce the start up current . There doesn't seem to be many manufactures making soft start units for single phase motors above 3KW. The other alternative is an inverter starter, this means you do not have to change your motor, it's a box which goes between the supply and motor. It's more expensive than a soft starter but by the time you've changed the motor and bought a soft starter, you would probably find it's cheaper to buy just the inverter.