RE: Motor Space Heaters aolalde (Electrical) 7 Jul 05 16:20Īctually, a lot of strip heaters are rated for high temperature operation so that they will work well when heating metal plates or the underside of a corn cob meal parts dryer. Many strip heaters are capable of having up to 600V applied however. Re: my statement about this being the same as a 480V 1000W heater, higher voltages are sometimes a problem because of spacing of terminals, wire insulation rating etc. they could have just put a resistance value on the label and been done with it, but that is too confusing for the masses. For convenience, the label on the heater says a wattage at a particular voltage so that you know where to start from, but beyond that it doesn't really matter. Since the surface are is also fixed, the watt density is controllable by changing the applied voltage. The resistance is fixed, so the voltage you apply will determine the wattage of heat output. Beyond that, 'ratings' are just conveniences so that you don't need to get out your Ohm's wheel every time you want to know how much heat it will dissipate. Why not put a label on it that says it is a 60V 15.625W heater then too? Or a 480V 1000W heater? Its all the same unit.īasic fact: an electric resistance heater is just a resistor built so that it doesn't burn up when power is applied to it continuously. It is well known in the process heater industry that if you want a lower watt density, just drop the voltage! I suppose that they could take a 240V 250W heater and put a label on it that says it is a 120V 62.5W heater to please the masses, but that's just a waste of time IMHO. There is no need to make multiple versions of the same thing.

OK, my final diatribe on this, I promise. RE: Motor Space Heaters RRaghunath (Electrical) 6 Jul 05 00:36 'Our virtues and our failings are inseparable, like force and matter. Īllen Bradley used to make one as well, don't know if they still do. Motortronics makes one called the MWH Series. Thye cost more than the space heaters as a component, but you don't need to run separate wires and conduit to the motor, so the installed cost is usually less. If you don't have a VFD, you can also get a separate electronic Motor Winding Heater that does essentially the same thing. this will heat the motor from the inside out, much more evenly than with space heaters, and it gets to the rotor bearings better as well. If you already have a VFD, most new ones come with the ability to keep the motor warm from the inside by applying low current PWM or DC to the windings. Good point itsmoked (about the heater, not the hangover, an yes, that is a bit of an issue today ).

Motor winding heaters