I have an electronic timer (the kind where you can plug appliances
into such as coffee pots, crock pots, etc.)
125 VAC 15A General Purpose
125 VAC 15A Resistive
125 VAC 1250W Tungsten
125 VAC TV-4 1/3 HP
My question is, can I safely plug a small window air-conditioner unit
to this? The unit is 515 Watts, 4.8 Amps, and 5,000 BTU.
I'm not sure which spec I'm supposed to be comparing to (if any). I
assuming the specs on the label of the timer refer to its maximum
limits (correct me if I'm wrong).
A 1/3 HP single phase 115V motor may draw up to 7.2 Amps, according to
the NEC. So I'd say a device containing one or more motors that draws
less than this would fall within the timer's rating.
mart> I have an electronic timer (the kind where you can plug appliances
This is not my field of expertise, but 515 watts is significantly
greater than 1/3 HP. The only motor rating given appears to be in the
last line. I am pretty sure that TV-14 does not refer to a television
channel. ;=) My guess is that the low rating has something to do with
Thanks. The other thing to consider (not in this case, but for general
information) is the
'Tungsten' rating. That is (based on the timer ratings) 10A. This is
lower than the 15A general purpose rating since incandescent lamps
(Tungsten) have a high inrush current when cold.
In the OPs case, his load falls within the 10A rating anyway, so all is
well. Even though a window AC unit would be characterized as a motor
load rather than a lighting load.
Well, *you* mentioned 'starting requirements'. I was pointing out that is
the *interrupting* of inductive current that would be the issue, not the
This would be an issue even if it's just an inductive load such as a
solenoid. There is no in-rush/starting current with a DC solenoid, yet the
contacts would have to be over-rated for interrupting the current.
| Salm|> |>
|>> Or interrupting an inductive load. This usually takes a more robust
|>> contact design than simple resistive loads so they are rated for
|>> less when controlling motors.
|> That was what I was pointing out.
| Well, *you* mentioned 'starting requirements'. I was pointing out that is
| the *interrupting* of inductive current that would be the issue, not the
| initial closing.
I learned the hard way what current through an inductor wants to do when it
is interrupted. Back in the 1960's I had a Heathkit experimentation board.
It was powered by 4 C cell batteries (safe, eh?). I was playing with my own
circuit wirings and wired up the little relay with the coil and the normally
closed contacts in series. It became a little mechanical oscillator. One
thing I noticed was that it was a higher frequency than the other way which
was to wire the normally open contacts to short out the coil when closed.
It also had a nice blue arc as the contact opened (that should have been a
warning). Being curious, I touched the relay contact arm. Got a good jolt
out of that. That was no 6 volts.