Using AC current meter to measure DC current?

[Tibur Waltson]

DC current meter could measure DC currents. But is it possible to use a DMM
AC current meter (rated 1-1000A) to measure current draw on an alternator's
DC output to see if it could put out 30A on a Honda automobile?
TIA
Tibur

 

[John Popelish]

Tibur Waltson wrote:

DC current meter could measure DC currents. But is it possible to use a DMM
AC current meter (rated 1-1000A) to measure current draw on an alternator's
DC output to see if it could put out 30A on a Honda automobile?
TIA
Tibur

I assume you are talking about a clamp around AC ammeter. If so,
these produce a reading by transformer action, which does not work for
DC. If you want ot read the DC current in some conductor you might
try to borrow a hall effect amp meter from someone. These do respond
to the magnetic field of DC.

http://www.hotektech.com/GMCMetraclip70.htm
http://www.electrical-contractor.net/The_Store/AM/AM-ACDC-600A_600AT.htm

You would probably do better with a 50 amp, 50 millivolt shunt
resistor wired in series with the alternator, with a millivolt meter
connected to infer the current each millivolt represents one ampere).

http://www.powertekuk.com/currshu.htm

You may find one of these or the hall effect clamp on meters for a
reasonable price on EBAY.

You will also need some sort of load bank of big, low value resistors
to connect across the alternator, to bring the current up till the
voltage starts to sag to find out its capability at a given RPM. 13.4
volts divided by 30 amps is a resistance of about .45 ohms rated for
400 watts. This is something like a few yards of iron fence wire
dipped in a bucket of water with a big alligator clamp that can be
moved to adjust the current.

--
John Popelish

 

[ddwyer]

In article <8cda9997396da9234eb44a3b516dacac@news.bubbanews.com>, Tibur
Waltson <Toush@hi.com> writes

DC current meter could measure DC currents. But is it possible to use a DMM
AC current meter (rated 1-1000A) to measure current draw on an alternator's
DC output to see if it could put out 30A on a Honda automobile?
TIA
Tibur



moving iron ammeters measure DC current

--
ddwyer