O grand wizard of elektrickery please reveal the secret of:

[Gareth0123]

O grand wizard of the ancient black art of elektrickery please reveal to me the secret of: the 2P/4P on the plate of this single phase saw.

 

[daleyd]

Normally indicates 2 pole or 4 pole motor, though I always thought 4 pole was 1/2 the speed of a 2 pole but this seems to indicate the other way round if the 2p relates to 45 and 4p relates to 90??

Maybe I'm reading it wrong though.

 

[pedrobedro]

2 pole or 4 pole motor ?

 

[Gareth0123]

So, would I be correct in assuming that you can open up the control box and swap the wires around to obtain either speed.

Therefore, would it be possible to route the cables through a three position switch (on-off-on) to switch between 2P and 4P and make the two speeds easily selectable from the panel?

 

[MattF]

Normally indicates 2 pole or 4 pole motor, though I always thought 4 pole was 1/2 the speed of a 2 pole but this seems to indicate the other way round if the 2p relates to 45 and 4p relates to 90??

Maybe I'm reading it wrong though.

It's the other way around, is it not; The more poles, the higher the speed?

 

[rtbcomp]

^^ Not according to this

http://www.engineeringtoolbox.com/speed-electrical-motors-d_738.html

 

[Maker]

It's the other way around, is it not; The more poles, the higher the speed?

No, t'other way round.
A 2 pole motor turns at 2850 rpm , 4 pole turns a 1425 rpm, 6 pole is 950 rpm and 8 pole is 700 rpm.

EDIT:, rtbcomp beat me to it.

 

[CRB]

?Perhaps it relates to how much is put in the meter?

 

[Gareth0123]

Right O, I think I have it sorted now. I think that 4P represents 3 phase and 2P represents single phase on the same.

 

[rikrobson]

The sped would be the same with different phases as the frequency does not change. It may mean that it's a 4pole motor and goes half as fast with only two of the poles wired up. Ithingcyou are going to haven't get the gear ratios from the pulls and work it out that way

 

[DAPPH]

Do we take it as being known whether the saw is a belt driven off pulleys one or if it's direct off the end of the motor ?
I ask this for my band saw has dual speeds because it has two different sized pulley sets .

Can you put up a picture or three of the whole saw and indicate what brand it is ?

 

[Gareth0123]

It is a Warco cold cut saw

 

[daleyd]

Looks like its something to do with it being 3 phase, probably 2pole/4pole configuration but I reckon its the wrong way round, ie 2 pole is faster 4 pole is slower.

Maybe give warco a ring to see if they have any more info?

 

[ford34/2]

a Picture of the electrical connection box showing how its wired up now would be an enormous help. as for 1 or 3 Phase, surely there is an existing mains lead to give us a clue. I appreciate you have mentiond single phase, Again a pic of the box should help reveal the mystery

Stan

 

[ukracer]

EDIT:, rtbcomp beat me to it.

Unusual lol

 

[Maker]

Unusual lol

What's unusual, my poor punctuation, what does :, mean?

 

[piman]

Hello all,

I would have thought that if the manufacturer went to the trouble of specifying a two speed motor they would also have fitted a selector switch? (My SIP wood/metal saw has such a switch) The link to the website gives little information on the saw.

Incidentally when did we change from pole pairs to poles?

Alec

 

[daleyd]

Must have been longer than 22 years ago as that's when I did my apprenticeship and we only ever talked about poles, not pairs?

 

[MattF]

^^ Not according to this

http://www.engineeringtoolbox.com/speed-electrical-motors-d_738.html

Chuff knows where I got that idea from then. I'll blame it on getting older and shonky memory.

 

[rtbcomp]

As an aide memoire - 2 poles are further apart than 4, so the rotor has to go faster to get from one pole to the next in the same time.