Evil Robotics

Pancake motor

3/12/03 Pancake motor

I received the proposed weapons pancake motor from www.sciplus.com on 3/10/03. The part number is 33450. The price was $14.50 plus shipping.

The weight is 37.8 oz or 2.3625 lbs. The no load specifications are listed as follows; 1800 rpm and 550 mA at 6 Volts, 4000 rpm and 750 mA at 12 Volts, and 6300 rpm at 24 Volts.

This is a lot less than the EV Warrior. It's specifications are; 2150 rpm and 2.4 A at 12 Volts, and 4420 and 2.6 A at 24 Volts. Of course the EV Warrior weights 3.25 lbs without a mount. The flat mount offered by www.cncbotparts.com will weigh about 1.05 lb.

Since the power formula is a piece if pie; P(watts) = I(amps) x E(volts) The 24 Volt no load power is as follows;

EV power = 2.6A x 24V = 62.4 Watts

Pancake motor power = 0.75A x 24V = 18 Watts

This does not calculate the peak power, but should be some linear comparison. Since the peak power will be about half the total speed of the no load speed, and the specification is readily available for and EV Warrior, I will calculate the power of the pancake motor. Given the peak power of a EV warrior is 0.75 Hp at 24 Volts at 2210 rpm.

The peak power of the pancake motor should be; 0.75Hp x 18 Watts / 62.4 Watts = .216 Hp at about 3150 rpm

The power to weight ratios are as follows;

0.75 Hp / 4.3 lb = .174 Hp / lb for the EV Warrior

0.216 Hp / 2.36 lb = .0914 Hp / lb for the pancake motor

This data doesn't seem to great. The pancake motor will be wimpy. I may still be in the hunt for a weapon motor. This weekend I will try to hook up a plywood test structure and test the pancake motor and see if it will be destructive enough. Most likely the weapon blade will be a 2 lb lawn mower type blade. Look out 10 lb bag of potatoes!