This thread's subject is definitely worthy of some Schematics!
I'll cook up some with low and hi volts arrangements.
Being that the Nameplate of this Motor shows 200/400 VAC, the Delta Run config with low voltage jumper terminations on the 208 VAC System should be OK.

Don,

I was thinking lower speed/torque starting application to get things moving (things being some fluid and the Motor's Rotor), then applying Motor across the Line after a few seconds.
Along with this, there may be some problem with high enough System Voltage at the time of starting (things faulting out from the fire, just flat-out lower than normal Line Voltage at the time of starting, etc...), which is another reason why I chose to go down this particular thought path.
[Linked Image]

Like I said, most likely not correct, but worth a thought!

Seems the flicker factor of starting this Motor is overridden by the need to get the Fire put out
(or: Sorry for the lights dimming people, we have more important issues to address - one being these frikken flames are growing in intensity!!! Scenario).

Could you explain the benifits of a Reduced voltage (Wye/Delta) Starter for the 20 HP Fire Pump?

I'm at a loss, except for the reason previously mentioned; so if anyone has the definite reasoning, please pass it on!

Scott35

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!