Is the motor a standard type of three phase induction motor ? If yes, then it cant be wired to run at two different speeds.

The purpose of star delta connections is to start in star, thereby limiting the starting current, and to run in delta for full power operation. Alternatively it enables the same motor to be used on two different voltages. If each winding is 230 volts then it may be used on a 3 phase 230 volt system, rare in the UK but popular overseas, or it may be used on a 230/400 volt system.

If each winding is 400 volts then it may be run in delta on a 230/400 volt system, or in star on a a 400/690 volt system.

For two speed operation you need either a special motor, with two sets of windings designed for different speeds, or more likely these days, a standard motor connected to a variable frequency drive.

The speed difference between Star (slower but higher torque, ideal for starting) and Delta (bit faster and lower current) isn't going to be that much where I would class one as low speed really. You say you have 1 & 3 switching on start up, then it reads like only 2 is engaged in slow speed mode (which if your trying to make this Delta would actually be high speed). 1 should also be engaged as well or have I just read that wrong?

Star Delta Starter Explained - Working Principle - Bing video

Z.

Speed torque......

The Speed Torque Curves for a Star-Delta Starter, 28/9/2016 - YouTube

Z.

The motor does zero. I feel the circuit is incomplete.

Or possibly lines have been swapped around - so that one winding has say L1 at both ends, another winding L2 at both ends and ones L3 at both ends? Motor then 'has power' but no p.d. across any winding so would do nothing.

   - Andy.

Any chance of a circuit of what you have wired ?  - photo of a back of a (large ! ) envelope sketch of the 3 or 6 motor windings  and associated contacts would be fine, and also the make or model of the motor. And, ideally, a photo of the winding ends inside the motor wiring box.

Unless the high low is more of a torque setting than a speed (and on a pool pump torque changing may be what you need) then Star-delta is not the right sort of motor, S-D does not change the speed as such.

For true dual speed the  only kind of motor is  a specially wound one that can be altered to behave in two ways, to change say between say 2 and 4 poles per revolution,  (or 4 and 8) and that involves rather more winding ends in the box  than a normal one.

A normal star-delta always energises the poles at the same rate, it just changes the voltages reaching those windings from 230 during spin up to 400V during run, a true dual speed is something else as the no of poles per rotation is also changed.. A vari-pole motor is not Star-delta, though it looks casually like it and the fast slow switching has much in common.

Even before VFDs were available those were unusual and mainly turned up only in washing machines and at lower powers than this. Nowadays a simple 3 winding motor and  a VFD is more common.

Rare, but it still may be.
The clue is that there are twice as many ends of windings in the box (12 ends not 6 but still 6 terminals) so that pairs of poles may be energized together in the slow speed as one double width pseudo pole and 
slewed between phases in the fast mode. This wiring illustration may explain better. Note there are two approaches, one gives a more or less constant torque at both speeds, and the other a more or less constant power  (high torque at low speed), as when the poles are excited as pairs, they may be // or series. If it is not just  S-D then closer than normal attention to the maker's data may be needed.

Mike.

The motor windings would have been wound for Star or Delta connection and importantly - to run at the same speeds; the current, torque and hence kW rating will vary though; by 1/3 on each type of connection winding. If the transition time was too lengthy, the speed and torque will fall unduly, causing stall; likewise, if the starting torque is too great.

As I recall the noo, this type of motor was designed to reduce the physical size of a D.O.L. motor - (physical mass for heat dissipation/expense), in accommodating the required starting torque.  

Jaymack

Sounds like the original may have been a Dahlander motor and the replacement is a standard star delta. Both 6 wire with 3 contactors but the winding arrangement is different in the motor.

Thanks, Dahlander - that's the name ..  age is a marvelous thing, but for the life of me I can't remember why. See in low speed that the poles are magnetised as pairs of the same polarity to emulate a single larger pole.

Be aware that the wiring may vary.

Not quite star delta....

Pole windings energizing sequencing around armature for one of them and a normal S-D compared.

Strange, my post from yesterday seems to have Gone. Mike I suggest you fit a VSD, it will be cheaper than a new motor and just think of all the new features, variable speed, emergency stop, bells and whistles! Oh and of course you can throw away all those nasty contactors!

Regards

David