motor contactor vs lighting contactor

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gobblerhuntr

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Can someone describe the differences between these two for me please? The lighting contactor seems to be a lot more expensive than the motor contactor.
 
The motor contactor (starter) will also include provisions for installing the overloads and will have aux contacts
 
The primary difference is in the contact material and its resulting ratings.
For example:
A NEMA Size 1 motor starter is continuous rated 27A for motor starting and only 15A for "tungsten lamp loads" (fluorescent lamp loads are treated like motor loads).
A NEMA Size 1 lighting contactor is rated for 30A fluorescent lighting and 20A for "tungsten lamp loads".

Another difference is in the design for additional features and accessories. Lighting contactor designs include an option for mechanically held (latching) construction that is not needed in a motor starter.
 
This may be obvious, but lighting contactors often have more contacts than motor starters. And lighting contactors can be electrically held (like a motor starter), or mechanically held.

Steve
 
In that case, if they're to all be switched together (and presuming they lights have their own panel), you might want a single large contactor to switch the entire panel.
 
LarryFine said:
In that case, if they're to all be switched together (and presuming they lights have their own panel), you might want a single large contactor to switch the entire panel.
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My experience is the inrush from a 400A HID lighting panel being switched by a contactor is often enough to trip the 400A feeder breaker. I like to keep my switched ballast circuits to 200A max.
 
jim dungar said:
A NEMA Size 1 motor starter is continuous rated 27A for motor starting and only 15A for "tungsten lamp loads" (fluorescent lamp loads are treated like motor loads).
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When you say fluorescent lamps loads are treated like motor loads are you referring to the fact that they strive to produce a constant power output.

I was looking at a particular 100W light recently and noticed that it had a multi-tapped ballast and that with lower voltage the light drew more current. I would think that a light would act more or less as a resistive element, and therefore a reduced voltage input would create a reduced current draw. Is there something in the ballast that causes the light to produce constant power and thus exhibit this relationship?
 
mull982 said:
When you say fluorescent lamps loads are treated like motor loads are you referring to the fact that they strive to produce a constant power output.

I was looking at a particular 100W light recently and noticed that it had a multi-tapped ballast and that with lower voltage the light drew more current. I would think that a light would act more or less as a resistive element, and therefore a reduced voltage input would create a reduced current draw. Is there something in the ballast that causes the light to produce constant power and thus exhibit this relationship?
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That's one main function of a ballast for either fluorescent or metal halide lights - keep the power output constant even if the input voltages change. The other main function is starting the lamp.

If you think about it, its probably very rare (if ever) that you see a fluorescent or MH fixture dim when a condensing unit kicks on.
 
mull982 said:
When you say fluorescent lamps loads are treated like motor loads are you referring to the fact that they strive to produce a constant power output.
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I was strictly addressing the construction on the contacts of the controller. In this regard, the power factor and inrush magnitude and duration of a fluorescent ballast are similar to those of induction motors.
 
mull982 said:
I was looking at a particular 100W light recently and noticed that it had a multi-tapped ballast and that with lower voltage the light drew more current. I would think that a light would act more or less as a resistive element, and therefore a reduced voltage input would create a reduced current draw. Is there something in the ballast that causes the light to produce constant power and thus exhibit this relationship?
Click to expand...
Yes. In a magnetic ballast, that would be the multiple taps on the primary winding, like a multi-voltage control transformer in an HVAC unit. In an electronic ballast, the circuitry uses whatever current is necessary to maintain the required power level, at the voltage supplied to it.

Added: There's a profound difference between applying different voltages to a given impedance, and applying different voltages to equipment designed for those differences. The multi-tap ballast is basically the same as having ballasts with different voltage ratings.
 
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LarryFine said:
Added: There's a profound difference between applying different voltages to a given impedance, and applying different voltages to equipment designed for those differences. The multi-tap ballast is basically the same as having ballasts with different voltage ratings.
Click to expand...

I guess what your saying is that applying different voltages to a given impedance will result in different current values. However equipment designed for voltage differences have impedance values that change depending on what voltage rating they are set for. As an example, changing a tap might chagne an impedence.
 
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