F5

F5

jueves, 30 de marzo de 2017

Star Termination vs. Delta Termination.

Star Termination vs. Delta Termination.

Regardless of what type of winding is done, we have the option to finish it Star or Delta.
It is said that at the same number of turns the resulting Kv will be 1 for Delta and 1.73 for Star. And that the current will be 1 for Star and 3 for Delta.

Which of the two endings is better or more effective.

Assuming we are looking for a fixed Kv, if we pack the same wire and the fhase resistor is the same, then the motor will be the same. Regardless of termination.
For this we use as an example the Motor HXT 750

Originally it has a DLRK winding,

18T, Delta,
Composed of 7 wires of caliber 30AWG,
80 inches in length.
Finished in Delta.
With a Kv of 750
Resistance per phase of greater than .061 Ohms.
Stator with an area of 28.2mm2 per slot.
A Copper Pack of up to 60.73%



 In an motor the Star termination phase is composed of only two coils.
thus. Fig.1
The resistance of the wire for two will be equal to one fhase.

In an motor, the delta termination implies that a fhase is composed of the 3 coils.
In this way Fig.2
The resulting resistance will be .66 of the resistance of one of the wires.





Trying to reproduce the same kv of the original, we find with TC 7.2 that:
In Star DLRK deal: 10T, 779 KV,
In Star HPDLRK deals: 21T, 742 Kv.
In Delta HPDLRK deals: 36T 750 Kv.
In Star LRK deals 20T, 742 Kv,
In Delta LRK it is occupied 34T, 756 kv.

Ver Fig 4



The resistance between phases is more .061 ohms in the original or stock motor.
Looking for the same percentage of wire packing as the stock is about 60.73% and a wire length of 80 inches (about 25AWG)


In Star DLRK deals: 10T, 779 Kv, 43 inch, 18AWG, 64.79%, Rm = .050 ohms.
In Star HPDLRK deals: 21T, 742 Kv. 2 / 46.2 inch. 22AWG, 56.4%, Rm = .062
In Delta HPDLRK deals: 36T 750 Kv.2 / 77 inch, 24AWG, 61.65%, Rm = .599
In Star LRK deals 20T, 742 Kv, 44.1Inch, 19AWG, 52.5%, Rm = .059
In Star LRK deals 20T, 742 Kv, 44.1Inch, 18AWG, 64.79%, Rm = .0469
In Delta LRK it is occupied 34T, 756 kv. 72.9 inch, 21AWG, 60.7%, Rm = .052

Rm varies with the packaging and not with the scheme.
With the exception of LRK that occupies less Turns
 
For the same kv. (less wire longitude)