[vcf-midatlantic] Off topic-testing 3 phase power

[William Dudley]

To test current, you need a load, either the thing you intend to power, or
an equivalent dummy load. 400v @ 16A is going to need one hell of a big
resistor.

To measure current, hook up the load and then measure voltage. I = E/R.

Optional extra credit: observe the waveform under load to make sure that
it's sufficiently sinusoidal.

Bill Dudley
Retired EE


On Jul 8, 2017 6:38 AM, "Ben Greenfield via vcf-midatlantic" <
vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:



---------- Forwarded message ----------
From: Ben Greenfield <ben at cogs.com>
To: vcf-midatlantic <vcf-midatlantic at lists.vintagecomputerfederation.org>
Cc:
Bcc:
Date: Sat, 8 Jul 2017 08:35:57 -0400
Subject: Off topic-testing 3 phase power
Hey All,

I find myself needing to verify that an outlet is supplying 16 amps at 400
volts Alternating Current at 50 Hz. I have verified the voltage with a
multimeter but feel I should be more thorough.

I’m trying to purchase an appropriate european socket tester which is much
cheaper if not as versatile as Fluke 109-104.

 I also have a Tektronix 2355 which I think I could measure each line on
it’s own channel to measure the voltage and the phase. Is there a safe way
to measure current with this oscilloscope?

Thanks,

Ben