3 ph contractor conversion to 1 ph

[pete.willerton]

I have a 3 phase pump and as many people maybe aware the grundfos 3ph pumps are hard to get hold of and they offer a single phase alternative ..:
So I have a 3ph and earth supply and need a 1ph

I know I could just take two fuse's out but a college has mention about this theory

Line conductor into T1 of the contactor then out the load side and then looped round to T2 and then out the load side to the pump and the neutral in T3 of the contactor and out to the neutral of the pump..
Is this correct ?
It's something to do with the overload not being able to function with only one line conductor ?

 

[Darkwood]

Yes thats fine - some overloads need to see current balance on all 3 poles or they may treat it as a phase down and not function. You need to check though that the coil is the correct voltage it may have been 400v? Wiring on the control may need alteration if you replace a 400v coil with 230v.

 

[Bobster]

We use those pumps on nearly all the sites I look after, never had a problem sourcing them, do you have to use that brand specifically?

As what darkwood has already stated there's a bit to consider, a single phase equvalant motor will run at higher current, will the existing switchgear and cables take it?

 

[pete.willerton]

The new motors are the grundfos magna 3d ... They take around 0.2 amps to run if I remember correctly

 

[Bobster]

Is 0.2amps a typo or actually what they use? This pump must be tiny.

 

[snowhead]

Magna 3 or 3D require no external motor protection.
Bin the overload.

 

[pete.willerton]

The magna one is 0.74 amps max

 

[steve50]

have you tried these people have used them in the past Heat Pumps, Booster Pumps, Submersible, Grundfos, Lowara, Blagdon, KSB

 

[big-steve]

I condemned two 3 phase grundfos pumps on Friday at 2 o'clock I sourced collected and fitted replacements by 5 o'clock

 

[JD6400]

have you tried these people have used them in the past Heat Pumps, Booster Pumps, Submersible, Grundfos, Lowara, Blagdon, KSB

They have just gone straight onto my favourites bar !

Top bit of info , as every different new supply source may help one day ! Thanks for that one .:hurray:

 

[TF and the wire]

You don't say whether you have a neutral. If you don't, you won't have the 230v needed for the 230 v motor,

 

[shanky887614]

You don't say whether you have a neutral. If you don't, you won't have the 230v needed for the 230 v motor,

? He can just remove two of the cores from the other end and mark them up as
red as brown,
Yellow as spare
Blue as blue

Then reconnect the blue at both ends as a neutrel.

Why do people try to make this so complicated.

Obviously the circuits protection and o/l will probably need changing though