Mike wrote:

Jeff Wisnia wrote:


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



When I put the probes on A and B and switch lights on (I am testing on a similar
light set up as the problem one) the meter momentarily shows to 24V and then goes
to zero. Same thing with switching off. I can't figure why? Do I have a problem
with me meter. It has worked fine otherwise.

Questions:

Are the "switches" normal toggling ON-OFF types or are they some sort of
momentary push buttons?

From what you just wrote, the control voltage might just be DC and not
AC and you have your meter set to measure AC voltage. That could account
for the meter momentarily "jumping" to 24 volts when the coil is
energized OR deenergized with DC voltage.

Try setting your meter for DC measurements, try again, and report back.

Jeff

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