magnetic starters

[danno]

If your breaker, wire and thermostat control are all rated greater than the amps of your motor, is there still a good reason to have a magnetic starter?

My 2 HP motor on my Delaval 75 is rated at 12.5 amps at 230 V. I was going to install wiring and thermo control of at least 20 amps, maybe 30 (in case I run a bigger motor in the future). Any reason to run a magnetic starter?

For running 220, anybody know whether I need 2 wire and ground or 3 wire and ground? I was thinking of running either 10 gauge SO or buried.

[royalmaple]

If you are not sub feeding a panel that needs 115v, then you can use say 10-2 with ground and just use your two hots and 1 ground. 10-3 + ground would only be used if you needed the neutral. I am assuming a 30amp circuit.

I ran 10-3 + ground to the Sugarhouse since I wanted some 115v circuts, but for the pump I only need my two hots and ground, so I can ignore the neutral.

[powerdub]

A motor at start up can draw some pretty heavy duty current and it will vary given the conditions. One day it may be 20 amps the next if things are a little colder it could be 45 amps. It may be for only a second or three but over a short period of time it will burn the contacts out of a thermostat control. The day it does will more than likely be the best run of the year and the day it does not get checked. I would consider it good and cheap insurance.

[danno]

As you may be able to tell, I don't do electric. I've seen magnetic starters as low as $60 and as much as $300. Can someone give me an idea of what I need to run a 2 hp motor, 220 volts, 12.5 amps?

[Maple Hill Sugarhouse]

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[danno]

Maple Hill - that's a ventilation control box - does that do the same thing as the magnetic starter?


Dan

[Maple Hill Sugarhouse]

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[Parker]

I also dont do electric,,but I know a fellow that does,,and he set up my pump in Hill for me,,This is what he told me,,my temp control is a 120 volt unit,,my pump is a 220 volt unit,,there is a magnetic starter between the thermostat and the pump,,the temp control tells the mag. starter when to turn on and off,, the magnetic starter handels the surge in amps of the moter starting and carries the amp load of the moter running,,,he said there were 240 volt temp. controls we could run,,but he would still recomend a starter between the pump and the therm. as they are built to handel the heavy draw of current when the moter starts,,that way you dont fry your thermostat,,I THINK the starter I am running is a grainger 4DD96 with 2 thermal units (1H623),,Mabey you could call your local Graingers,,give them the info on what you are looking for and they could help make sure you got what you needed..........

[royalmaple]

Take this with a grain of salt, but have you seen the wiring in most dairy farm barns? They are lets just say a little left of right(correct).

If you are using dairy pumps, think of what their life was before you got them. Most were running on 110v, and 1/2 on extension cords or overloaded circuits.

I was going to run mine from the box to a disconnect and to the pump. The disconnect would act as my switch. I think you need to look at the size of your pump motor as well. It is a different story if you are starting and stopping a 5hp electric motor vs a 3/4 hp electric motor.

my .02 which is worth -.10

[Parker]

My pump in Hill has a 3HP 220V moter,,and with that many taps on it I dont mind spending the $180 for a magnetic starter that should make the system last a long, long time,,,,,,my .01cent,,,