- Thread starter Trev3635
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brightspark
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a fortune to run a compresor as the starting load under presure is highHow much would an inverter cost me then?
be cheaper to convert to single phase .what size motors on at the present eg horsepower -kw -rpm
brightspark
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the older motors are 415volt star wired only . the newer ones are dual voltage star wired for 415v or delta wired for 240v, both 3phase
Hello Trev,
it depends on the motor size, have a look here, http://www.drivesdirect.co.uk/Products/Digital_Inverters.htm.
3 H.P. 240 to 240 about £300, 240 to 415 nearly £500. As your motor will run on 240 three phase it's still quite expensive.
Alec
it depends on the motor size, have a look here, http://www.drivesdirect.co.uk/Products/Digital_Inverters.htm.
3 H.P. 240 to 240 about £300, 240 to 415 nearly £500. As your motor will run on 240 three phase it's still quite expensive.
Alec
Deffo 3 phase - 3 wires and no (visible) capacitor.
You can it off a 415V 3Ph supply or change the straps in the motor (to delta) and run it off a phase convertor at 240V single phase.
Or swap it for 240V single phase motor - try Kenworth in Huddersfield 01484 660222 we use them at work - think they do up to 3Kw single phase but they ain't cheap and need big juice to run !
Garreth
You can it off a 415V 3Ph supply or change the straps in the motor (to delta) and run it off a phase convertor at 240V single phase.
Or swap it for 240V single phase motor - try Kenworth in Huddersfield 01484 660222 we use them at work - think they do up to 3Kw single phase but they ain't cheap and need big juice to run !
Garreth
scarecrow
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i wonder if there in the box on top of the motor
(ps)you could also used one of thees to run it http://cgi.ebay.ie/GO-KART-KARTING-...s_Vehicles_Other_Vehicle_Parts_Accessories_ET
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outofthefire
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Post a photo of the plate cos a lot of the info given so far is based on speculation
langy
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Shouldn't it have 4 wires for 3 phase ??? On my compressor the start caps are in the black box, so are not obvious.
Hello Brightspark,
"the older motors are 415volt star wired only", I'm sure you meant delta wired as a star connected 415 will run on 240 delta.
Langy, "Shouldn't it have 4 wires for 3 phase", only if you count the earth wire, no neutral required.
Alec
"the older motors are 415volt star wired only", I'm sure you meant delta wired as a star connected 415 will run on 240 delta.
Langy, "Shouldn't it have 4 wires for 3 phase", only if you count the earth wire, no neutral required.
Alec
"a star connected 415 will run on 240 delta" - yes, it will, but to configure the motor as delta you have to be able to get to the common point of the star. On an older motor this will be hidden inside; the motor will only have three terminals rather than six, and there will be no configurable links.
langy
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Yeah I appreciate you need to count the earth as well, this thread seems to have got to 3 pages without an answer ??? I would of thought a pic of the wire would of had it sorted by now ???
Hello Langy,
if you look at my first post #2, you will see that I said it looked like three phase.
Reasons, three wires from the contactor to the motor, single phase would just have two, no visible capacitor, I know some have internal capacitors so not conclusive there. But really the name plate on the motor would tell straight away, unless of course it's missing.:-)
Alec
if you look at my first post #2, you will see that I said it looked like three phase.
Reasons, three wires from the contactor to the motor, single phase would just have two, no visible capacitor, I know some have internal capacitors so not conclusive there. But really the name plate on the motor would tell straight away, unless of course it's missing.:-)
Alec
Hi, and thanks for all the replies they've been really informative. I asked a colleague who is an electritian to come and have a look (now £10 lighter) and he says it's definately 3 phase, as was suggested in some of the posts four wires are 3 phase and he took a look at the motor rating plate and it confirms 415v and it is not the original motor and has been converted from single to three phase.
So thankyou very much to everyone who posted and tried to help me out it is very much appreciated.
So thankyou very much to everyone who posted and tried to help me out it is very much appreciated.
Definitely 3 phase ! Square terminal box (no capacitors in there ! They'd be massive for that size of motor) and 4 wires - blue, brown, black and a green/yellow earth . I work on these things every day........
Needs a phase converter or sell it and by a single phase one !
Garreth
Hello Edie,
"the motor will only have three terminals rather than six"
In my experience the vast majority of three phase motors have six terminals, (apart from H.V. motors which run in star). But the U.K three phase motors generally were designed for 415 to be applied to delta, so allowing star\delta starting, which of course needs six terminals.
Alec
"the motor will only have three terminals rather than six"
In my experience the vast majority of three phase motors have six terminals, (apart from H.V. motors which run in star). But the U.K three phase motors generally were designed for 415 to be applied to delta, so allowing star\delta starting, which of course needs six terminals.
Alec
