Laplacian
Electrical
- Jul 15, 2002
- 246
What is the best arrangement for a single zone of multiple parallel heater probes from a load balance perspective on the SCR controller? The application is as follows:
* 6-SCR,3-phase,480V controller, phase angle fired
* 112.5KVA, 480V Delta - 100V Wye (58V ground), 3-phase encapsulated transformer
* 108 - 750W heater probes (can be any voltage)
I was considering connecting them all in parallel delta for 90V rated probes.
The issue is potential half cycle faults due to load imbalance when individual probes fail and open up. Probe replacement is difficult and requires costly downtime.
What parallel connection would result in the most balanced load as seen by the SCR controller through the delta primary transformer winding?
Would it be a 4-wire wye connected heater arrangement? Ungrounded wye? Or delta? Note that each probe is individually protected. I can specify 50V or 90V probes from the manufacturer.
Thanks for any input.
* 6-SCR,3-phase,480V controller, phase angle fired
* 112.5KVA, 480V Delta - 100V Wye (58V ground), 3-phase encapsulated transformer
* 108 - 750W heater probes (can be any voltage)
I was considering connecting them all in parallel delta for 90V rated probes.
The issue is potential half cycle faults due to load imbalance when individual probes fail and open up. Probe replacement is difficult and requires costly downtime.
What parallel connection would result in the most balanced load as seen by the SCR controller through the delta primary transformer winding?
Would it be a 4-wire wye connected heater arrangement? Ungrounded wye? Or delta? Note that each probe is individually protected. I can specify 50V or 90V probes from the manufacturer.
Thanks for any input.