Mike wrote:
Meat Plow wrote:


On Sat, 17 Nov 2007 19:50:55 +0200, Mike wrote:


I have a light that refuses to go on.

The light switch (wall type) is connected to a relay. Now the relay won't
"click". It used to work a couple of days ago. The relay has operating voltage of
24V which switches a 240V line (lights).

I would like to test (using a voltmeter) where I'm having problems. How do I
measure if 24V is going through the coil/magnet.

The relay box looks like this (wires go to points A,B,C,D):

A 24V b
-------------
| |
| |
| |
| |
| |
C------------D
240V

When the switch is off volmeter shows 240V between C and D

When the switch is on volmeter shows 0V between C and D

How do I measure voltage in A and B?

If C and D drops to zero then I would assume the relay is closing.

The voltage on A and B should be 24 volts when the switch is on.


Thanks for the quick reply.

The relay is rated 24V-8V. I'd like to know what I am getting.

What if I (using my voltmeter) connect A or B to ground Should I then get 24V on
my meter.


Not neccessarily, unless A or B happens to also be grounded, which would
not necessarily represent a fault.

Put your meter probes across A and B. You will probably read zero when
the switch is OFF and should read 18 to 24 volts when it's ON.

If you get the 18-24 volts with the switch ON, but no "click", yet C and
D drops to zero as you say, then I'm missing something.

Do you know where the low voltage source running through the switch
comes from?

More details please...


Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.98*10^14 fathoms per fortnight.