What is a "Growler"? (electrical test device)

Jan 29, 2004 16 Replies

Fellow RCMers,



I've been reading a book from the 50's that describes different kinds of electrical motors and how to repair/rebuild them. In one part, it very briefly recommends using a "growler" to test an armature. Unfortunately, the reference was short and pretty obscure, and I was left in the dark as to what the test would even accomplish. Does anyone know the answers to any of these questions?:



1) What does a growler measure?
2) How to you correctly use one?
3) Can you build your own?
4) Has it been replaced by a newer device? I notice that neither HP or Fluke offer one, so I suspect it may be antiquated.

This question might be better suited for rec.electronics or something, but I know the metalworking hobby tends to generate piles of broken motors (got a few myself) so I thought I'd check with y'all first.



Thanks! Dave Doerschuk


Look at these sites, maybe it'll help explain them:

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Dave Young

Dave, Check out this site. It will explain it for you.

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the growler is a test device that will induce a magnetic field into an armature and then allow you to check for shorts and opens in the windings. It sort of acts like the primary of a transformer. It is generally used with motors that have commutators. (DC motors, repulsion and universal motors, auto starters and generators, etc.) HTH PJ

It's a 2-part device. The first part is a U-shaped chunk of iron with ends of the U in a vee shape so that an armature can be set inside them. A coil is wound around the U and AC is applied to it.

The second part is a set of probes and some kind of indicator.

By putting the suspect armature in the crotch of the U and applying power to the coil, you induce a voltage into the windings of the armature. You can then probe the segments of the commutator and test for shorts or opens.

It's called a growler because of the obnoxious sound the armature makes rattling against the U shaped pole.

Snapon still sells them:

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pdf/manuals/mt326c.pdf

A growler is a electromagnetic device for inducing an alternating magnetic field in a wound motor armature (usually DC or universal motors.) If there is a short in the armature, circulating currents will be induced. These circulating currents produce their own magnetic field that can cause the growling sound -- or in my own experience can be found by passing a thin strip of magnetic material like a hacksaw blade over the armature. Growlers look like a U or a V shaped stack of laminations with a coil of magnet wire wrapped around it. Try a company specializing in motor servicing tools -- perhaps Ideal or Stockdale.

Mill

Or of course your woman after you've downed a Growler full of your favorite beer....without sharing. Paul

I would (almost) bet that a "growler" is another name for a "current sniffer". With these you inject an AC current at one node and have the return located at some other node that is shorted to it and shouldn't be. Then, the "current sniffer" is an inductive probe that you wave back and forth along the wiring or trace (as the case may be) and when the tone (growl?) changes, you've found the physical location of your short. I believe that a company currently produces such a product under the trade name "Tone Ohm". If you like eBay, you can frequently pick up a used GenRad Bug Hound which is also such a device. It doesn't actually give an empirical measurement but helps you to (physically) locate a short.

Nope, not a Tone Ohm. Go back and read some of the other replies to find out what it is.

Hey, they have their own radio station now. Call letters are KPMS, the programming format is 23 days of rock and roll and then 7 days of ragtime.

They call it "PMS" because the term "Mad Cow Disease" was already in use.

I thought it was because " Rabies" was already in use. Maybe its an American thing........

Gunner

Liberals - Cosmopolitan critics, men who are the friends of every country save their own. Benjamin Disraeli

On Thu, 29 Jan 2004 15:53:30 -0800, Jim Stewart vaguely proposed a theory ......and in reply I say!:

And from your description of its use I would growl too.

Crotch...probe...power...voltage....grrr.

But yes, I remember using them. Lovely name and very apt.

**************************************************** sorry remove ns from my header address to reply via email

Spike....Spike? Hello?

On Thu, 29 Jan 2004 18:28:18 -0600, Jerry Wass vaguely proposed a theory ......and in reply I say!:

Otherwise known as an elect testicle device.

Please read my reply on crotch, voltage, probe etc. It probably applies.

**************************************************** sorry remove ns from my header address to reply via email

Spike....Spike? Hello?

Old Nick scribed in :

yup can also double as a tape eraser. cassette, 1/4" reel to reel, VHS. anything. just put a sheet of cardboard across the top and slide the tape around over the poles for a bit.

my Dad's one has a light bulb for that. the probes have 230 volts across them when switched on.

I've never been sure exactly what to look for with this thing. with my Dremel tha thad a couple of open windings I just found them with an OHM meter.

needle noddle nooooooooooooooooo

swarf, steam and wind

-- David Forsyth -:- the email address is real /"\

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