Growler

[wbd]

Hello,
I heard recently of a way to clear shorts off a 480 V delta system using what was termed a "growler". Has anyone heard of this and can explain it?
Thank You

 

[candu6]

I know a growler as a device to detect broken bars in an induction motor's rotor.

 

[wbd]

I should clarify - I meant grounds not phase shorts.

 

[DanDel]

candu6's definition of a 'growler' is accurate, in my experience.
Typically, ungrounded delta systems have had the 'three lamp' system, which shows if one phase has gone to ground. Each of the three lamps are connected between each phase and ground, and, for normal conditions, are all equally illuminated (dimly). If one phase goes to ground, that lamp will go out, and the other two lamps will illuminate brightly.
How to use a growler to find the connection to ground is not clear, since it is basically an induction coil.
There are other detection methods used for ungrounded systems. I have seen some GE switchboards with a 'pulse' system, though I am not familiar with the operation principle.

 

[alehman]

The pulse system is usually used on high resistance grounded systems. It periodically changes the grounding resistance to facilitate tracing the fault with an amprobe. Most major switchgear mfg's have pulser systems available.

 

[busbar]

 
Examples of pulsing systems for high-resistance-grounding:

http://www.geindustrial.com/industrialsystems/switchgear/notes/GEI-72116.pdf

http://www.sea.siemens.com/pde/product/Swbd_pdfs_3_29/LV_High_Resistance_Grounding.pdf

http://ecatalog.squared.com:8080/Te...ution/Low Voltage Switchgear/44022-921-01.pdf

There are low-range large-jaw clamp-on ammeters for fault tracing.

http://www.stbinc.com/products/fault/gf23.html

 

[wbd]

My understanding of this growler is that it is a stator coil from a rotor and is attached from a phase to ground in order to try to clear the ground by blowing it off (maybe high current to burn off ground???)

 

[DanDel]

Almost sounds like the operation of a 'thumper' for MV cable grounds.

 

[RRaghunath]

"Biddle" has (used to?)an instrument for detecting earth faults in un-earthed DC systems. The name "Growler" reminds me of that.

 

[RalphChristie]

wbd

I am not familiar with the name "growler" but to add to your and DanDel's comments:

We use a "thumper" (surge generator) to detect faults on buried MV cables. But sometimes, when there is a fault with a very low resistance, a thumper is not effective to find the location of the fault. Then we use an instrument called a burn-down (maybe a growler?) to circulate a high current through the cable to burn it, and to increase the resistance to find the fault with the "thumper"

Burn-down -

http://www.adret.co.za/Products/Burning/BU3500.htm

Surge generator -

http://www.adret.co.za/Products/Pinpointing/Surge Generators/surge generators.htm

Regards
Ralph