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I did enough surfing to know about the kind of motors used in electric room heater, but not able to finalize. The principle seems like working of an induction motor with a electromagnetic stator but not sure.

I need to decide one such small motor working at 220v AC which will be able to drive a fan blade. Further, the motor should be moist and humidity proof along with protection from 1000w heating element in close vicinity. Any links or clarfication will be helpful.

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    \$\begingroup\$ Usually, these are shaded pole motors, a simple kind of induction motor. \$\endgroup\$ – Janka Dec 26 '17 at 9:57
  • \$\begingroup\$ Yes, this is the term I was looking for. Now I am getting some relevant links :) \$\endgroup\$ – Prasan Dutt Dec 26 '17 at 10:07
  • \$\begingroup\$ Typically, at least in the heaters I have seen, the motor and fan blow cold air toward the heating element. In this fashion, the motor and fan blade do not actually get particularly hot. Make sure you use a thermal fuse so you don't cause a fire if the motor fails. \$\endgroup\$ – mkeith Dec 26 '17 at 17:23
  • \$\begingroup\$ Yes, thermostat is a must for any room heater or conduction cooktop. It is in my consideration. \$\endgroup\$ – Prasan Dutt Dec 27 '17 at 5:49
  • \$\begingroup\$ @Janka I found out that shaded pole motors are not much efficient and doesn't perform better for >50W. What should I choose for more power and efficiency? \$\endgroup\$ – Prasan Dutt Dec 27 '17 at 5:53
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Shaded Pole is really the best choice from a reliability standpoint for this kind of application. If you are concerned for the fan motor efficiency and don't want to use Shaded Pole, then the next logical step would be Permanent Split Capacitor (PSC). The issue is that when a motor is in the air stream, any kind of centrifugal starting switch arrangement, as found in Capacitor Start or Split Phase motors, will eventually become contaminated and cease to function. PSC has no centrifugal switch.

If absolute efficiency is paramount, then the new paradigm is to use an ECM; Electronically Commutated Motor. this is essentially a permanent magnet AC 3 phase motor that has it's own on-board inverter drive built-in to the end bell. The inverter accepts single phase AC input and converts it to 3 phase PWM to run the PM motor. They are by far the most efficient on the market now, upwards of 97% eff, but are going to cost a LOT more money up front than a Shaded Pole or PSC motor of the same rating. Some OEMs are using them anyway because they MUST get their product to meet certain efficiency standards, so they have no choice. The consumer is who pays the price ultimately though.

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