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Power Factor meter?
By Jerry, Section Controls Posted on Fri Apr 20th, 2007 at 04:20:35 AM MST
Picked up these meters yesterday.

I was helping a freind yesterday clean up an old TV repair shop. I came accross these big GE meters. They measure 6"X6" on the face and are about 4" deep accept for the power factor meter.
It has 6 conections on the back and a thing sticking out the back that looks like a motor?
The face has the specs.
5a, 240 volts, wire 2, S phase. I heard of power factor but sure what it is. I know its been discused here befor.
I was just wanderin? if this thing has any usfullness and how would I hook it up if it did?
I need to go help the freind more. I think the old TV guy that passed on had been doing service back into the 50s and maybe up to the 70s? But theres tons of neet stuff there.
Heres a few pictures of these meters.

JK TAS Jerry

Power Factor meter? | 4 comments (4 topical, 0 editorial)

Re: Power Factor meter? (3.00 / 0) (#1)
by Nando (nando37-at-tx-dot-rr-dot-com Correct theanti-spam) on Fri Apr 20th, 2007 at 08:57:17 AM MST
(User Info)

Yes, good use.

The PF meter would be good to define how the load affects the generator with it, PF( angle variations)

The PF meter needs two sets of inputs , one is the AC voltage and the other is the AC current, some of the meters have 3 wires ( one common), some have 4 wires.

Normally, the PF meter needed a current transformer with the burden resistor.

Nando

Re: Power Factor meter? (3.00 / 0) (#2)
by Flux on Fri Apr 20th, 2007 at 11:31:59 AM MST
(User Info)

Those meters almost certainly came from an alternator or more likely a synchronous motor connected to a grid. The Dc meter would have measured field current and the PF meter would have been used to set the excitation to suit the system. Many sync motors are used for power factor correction of a system as well as providing power. There are even machines run with no load to correct power factor known as synchronous condensers ( capacitors).

I doubt that you will find a power factor meter useful, it is a very specialised thing and is not something you can hang in a single phase circuit to directly measure load power factor. The other meters could be useful.

Flux

[ Parent ]

Re: Power Factor meter? (3.00 / 0) (#3)
by alancorey (alancorey@yahoo.com) on Fri Apr 20th, 2007 at 03:29:04 PM MST
(User Info)

Old meters are neat to look at, but don't seem to be very efficient. With every type of mechanical/analog meter you pay a price for using it. Voltmeters draw current, ammeters have a significant voltage drop ("burden" or shunt drop). If the magnets and bearings weren't very good they're worse. I've been in situations where I had access to boxes full of them and I only ended up keeping a few. These were "student grade" meters from Physics labs that had to be durable and were expected to get dropped and otherwise trashed so they were fairly cheaply made. Not as modern as the meters you're showing here, so yours might be better. The drawbacks on these are usually listed in the fine print on the bottom of the meter faces. I never saw a power factor meter though.

Alan

Re: Power Factor meter? (3.00 / 0) (#4)
by hiker (hiker.wild[at]yahoo[dot]com) on Fri Apr 20th, 2007 at 11:03:03 PM MST
(User Info)

hey jerry... i could use that ac meter..
is it up for sale?
should work great on my 300v pedgen..
are there only two leads on it ?

WILD IN ALASKA
[ Parent ]

Power Factor meter? | 4 comments (4 topical, 0 editorial)

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