Timers are expensive!

Ya, Iv got to agree; those numbers are way too funny to be true; If your paying $14 a month JUST to run a timer, that timer better be doing something really cool; like make you coffee; heat the tank etc… A 1/3 HP motor geared to move one revolution per 24 hrs could probably lift a small Jet; so I think there has to be an error SOMEWHERE….

As for timers in general I am VERY happy with my new ones; these are supposedly more accurate and im sure they pull nothing to run… I think Levithon(sp) makes them; so any electrical supply/lighting store should have them in stock… I got these are Home Depot…

DSCN3841.JPG


DSCN3844.JPG
 
Joephys aside from reading the label that states Rating: (and lists all of the measurements) you're being too literal with your calculations. Between the wide tolerances that the manufacturer allows for and the spin put on it by the advertising department the rated horsepower of a tool or appliance has little to do with the calculations. Go to Sears or Home Depot and compare the "5hp" Shop vac, and the 5hp air compressor. The advertised horsepower will not work out mathmaticaly.
 
chefkeith said:
The meter is getting some readings now. 0.07 Amps, 02 Watts, 0.01 kwh, and 16hours 15minutes.
Click to expand...

Last Update-
The meter now reads- 0.00 Amps, 00 Watts, 0.07 kwh, and 95 hours 51 minutes.

(I'm not sure why it now reads 0 amps and 0 watts. My guess in that this is a coil timer that gets winded automatically.

Estimate electrical usage -
monthly = 0.525 kwh = $.05
Yearly cost= 15.75kwh = $0.59
 
Last edited:
Yes cbsfkeith I just took a timer apart and it looks like the coil gets wound up a few times a day. But I would think each timer is different on that. I did do retesting on my timers and after about 30 minutes the watts want back to 0.
 
chefkeith said:
I'm not sure why it now reads 0 amps and 0 watts. My guess in that this is a coil timer that gets winded automatically.
Click to expand...

That is the same way old automotive clocks used to work. Technology marches on...... :)

v/r, N-A
 
JohnH. said:
This means that you can have a that much plugged into the unit. For those of you that have said that the timer means you can plug in a 1/3 hp motor, that is just plane wrong, 1875 watts= 2.5 hp."
Click to expand...

Nope, it's not wrong. It's a huge pad put in by the manufacturer of the timer for current demand. Fractional horsepower motors used around the house use way, way more current during startup as opposed to flat current usage at a steady state (under rated load at placarded operating rpm).

If you plug in a timer rated for 1875W (probably for a straight resistive loading only; incandescent lighting will have a lower rating on some timers), that small timer's contacts will not be robust enough to resist being damaged upon starting up any 2.5hp single phase motor, especially if it has any sort of loading on it (like v-belts, or having to overcome the rotational inertia of a pulley, or even the mass of a table saw blade). For e.g., a smaller 2hp single phase table saw in many cases will dim the lights in your garage when you flip it on, and the lights won't resume their former brightness until the motor has reached operating rpm...the current demand on startup is much higher than you think. (BTW, do NOT experiment and try to see if your household timer will work at 2.5hp by hooking it up to a table saw with the motor turned on to see if it will switch and start it up...it might do it a couple times before you fry it).

RTR said:
As I posted early in this thread, folks are failing to distinguish between the carrying capacity of the units and the unit's own energy comsumption. The units themselves use less power than night lights....Light switches, power cords, circuit breakers, timing devices, etc. are all rated for what they can carry and feed, not for what they themselves use when not even in use. I cannot believe this thread has made it to two dozen posts and we still have no common and accepted understanding of the basis for the discussion.
Click to expand...

He's right. It's all about rating. And like I said before, power requirements for a timer are miniscule. A single AA cell can run one for a long, long time. Just ask me how I know.

v/r, N-A
 
1/3 Hp

I would suggest that the 1/3 HP you are reading is what the timer will support as a controlled appliance. I've sceen single door garage door openers that were 1/3 HP. Not any where near the load of a door opener to run a small clock!
I would further suggest that the monthly cost to operate the timer itself, not the controlled appliances, should be less than 20 cents.
 
A timer is a switch.

I can't speak about the NEC, but according to the CEC (Canadian Electric Code):

* for non-inductive loads other than tungsten filament lamps, the switch cannot have a rating less than than the ampere rating of the load.
* for tungsten filament loads (light bulbs) switches must be "T" rated since they have a high inrush current when they are switched on as tungsten has a lower resistance at room temperature and thus draw larger currents until they heat up.
* For inductive loads (motors, high pressure sodium lights, and fluorescent lights) the switches must have an ampere rating of twice the ampere rating of the load. There are inrush current issues with motors, but there are also issues when turning off an inductive load with a poor power factor as the very rapid collapsing magnetic field generates a high voltage pulse or spike that attempts to maintain the current and results in an arc accross the switch contacts, potential welding, death and armageddon.

1/3 HP refers to a restriction on an inductive load you may wish to consider controlling with the timer.

If you've created some uber canopy with ungodly loads, you may wish to consider using the timer to control low voltage switching and a relay. Most of these timers were not designed for 2 w/gal applications.
 
:duh:

I'm such a dope, it was so simple. I had given up on this because the vast majority of posts people either didn't know what they were talking about or where completely missing the point.

I should have figured that out right away, but thanks wibber, you gave me the exact answer I was looking for :thm:
 
You must log in or register to reply here.
AquariaCentral.com
Top Bottom