shuttle car motors

[clinton garforth]

i have some questions about the shuttle cars we use underground in coal mining.
first question is about the conveyor motor it is a 3 phase motor 1000v ac,it has a slow and fast speed and uses a star / delta configuration to get the two different speeds.the motor is a 6 wire 6 winding system when in the delta configuration two windings are in series between 2 phases using 6 windings between all 3 phases and when in the star configuration 2 windings are in parallel between one phase and the star point using 6 windings between 3 phases and star point.i would like two know why they do this instead of your standard 3 windings in the star / delta configuration.


thanks
clinton garforth

 

[LLSolutions]

You need the 6 windings to be able to put them in series for the delta. 3 windings give you no ability to change configurations.

 

[boboelectric]

Good for you,Man. Wondering how those staters in those impossible to open NEMA 10 boxes fail due to dampness ,corrosion,flooding,ect, Keep in mind "Que Creek" THEY will come and rescue you,no matter what.

 

[clinton garforth]

You need the 6 windings to be able to put them in series for the delta. 3 windings give you no ability to change configurations.

i think if you consult your text books you will find that you can get a star and delta configuration using 3 windings and 6 wire configuration using 3 sets of contactors 1 is used as a line contactor and the other 2 are used for getting a star and delta configuration

 

[don_resqcapt19]

Clinton,
How do you have 6 windings with 6 wires? I would expect 12 wires. With 12 wires you can wire windings in series for high voltage and in parallel for low voltage and still get the wye and delta configurations. I am not sure how you change speeds by changing from wye to delta as the speed would be based on the frequency of the supply.

 

[jcormack]

6 wire (lead) 2 speed motors are quite common, not just in the mining industry

6 wire (lead) 2 speed motors are quite common, not just in the mining industry

here are some connections

http://www.joliettech.com/3ph_motors_2_speed_single_winding.htm

bobo - mining enclosures are regulated and approved by MSHA, not NEMA

also NEC does not apply underground (except for certain portions of the 1968 NEC)

you change speed by changing # of poles - these motors are designed to run at lower speed continous, not to be confused with wye start/delta run that can only use wye for short period of time .

 

[Ranch]

NEC does not apply underground (except for certain portions of the 1968 NEC)

Do tell oh John Bob .......

And there exists a 1000V VFD exactly suited for you. But best we say more specifically 995Vac RMS .... Yes?

 

[Ranch]

6, 9 or 12 leads, why not three? With some fancy new leading edge of trailing technology, we simpy work around it

Death to full voltage starts! Windings be damned!

 

[Cold Fusion]

(cut) I am not sure how you change speeds by changing from wye to delta as the speed would be based on the frequency of the supply.

Design D motor? It's a stretch - but should work depending on the turndoun.

edit: Whoops, missed jcormacks post. Add:
As jcormack said, possily a 2pole/4pole motor. This would fit with "6 leads/6 windings".

cf