Three-phase rectifier question

[SolarPrestige]

With three-phase rectifiers, does the phase rotation of the supply matter? I ask this because I have a series of battery chargers which are happily in service, but I will be taking them off their switchboard and feeding them with a diesel generator supply for a while. This allows maintenance to be done on the essential switchboard which is feeding the units.

Will the input stage of these units (thyristors I expect but I didn't check before writing this) care if the genset phase rotation is the opposite to what it was getting previously? Seems to me it shouldn't care, but I don't want to kill anything by getting it wrong.
thanks,
Greg

 

[jraef]

Should not care.

If it is a diode bridge rectifier, it absolutely will not care. If it is an SCR based rectifier it MIGHT, but only if the designer was lazy and stupid about how the firing circuit determines the phase angle when ramping up... (in some designs, an SCR based rectifier is "ramped" to full output as a method of limiting inrush current drawn by the capacitors when first energized, as opposed to a pre-charge circuit using a current limiting resistor and bypass circuit or NTC resistor). If you don't know, find the bridge rectifier section of the charger and look at the thyristors. If they have gate wires on them, they are SCRs. If not, they are diodes.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[SolarPrestige]

Definitely Thyristors in the input stages. The chargers do have a soft start feature as well. These are late 1990's Gutor brand chargers if that helps anyone recognize whether the input stage will be polarity sensitive.