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I have a question about the frightprops Wiper motor!! I noticed on their site that you can run the motor with a 5 volt power supply for a lower RPM. Is this bad for the motor, shorten the life or cause overheating? Thanks HH
 

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I have a question about the frightprops Wiper motor!! I noticed on their site that you can run the motor with a 5 volt power supply for a lower RPM. Is this bad for the motor, shorten the life or cause overheating? Thanks HH
No problem at all running on 5v. I have a couple props that run continuously on 5v, no problem. Just keep in mind that the motor will have less torque on 5v vs. 12v. If you need the extra torque, a PWM control using 12v is a better option.
 

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Thanks J-Man and Diabolik, I figured it was ok since they sell them that way!! But for some reason it just doesn't sound right!! I don't need the the extra torque, I am just using it for turning the crank on a giant Jack in the box!! Overkill I know but the crank is 3/8 steel rod with a heavy wood handle. I just want to make sure it will last a long time with no problems!! Again thanks for the replies!! Ordering a wiper motor now!! HH
 

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The torque of a motor is proportional to the current flowing through it while the angular velocity of a motor is proportional to the voltage across it.
So a 5 volt or 12 volt power supply, both at 5 amps, will have the same torque, but different speed. So you'll have plenty of torque.
 

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The torque of a motor is proportional to the current flowing through it while the angular velocity of a motor is proportional to the voltage across it.
So a 5 volt or 12 volt power supply, both at 5 amps, will have the same torque, but different speed. So you'll have plenty of torque.
A motor that is designed for a certain voltage will be weaker if the voltage is lower, doesn't matter how many amps you put to it. Perfect example, your car battery and starter. The starter is designed for 12v, if your battery drops to about 11v, you ain't gonna start the engine even though the battery probably has way more amps than would be needed at 12v.
 

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Thanks J-Man and Diabolik, I figured it was ok since they sell them that way!! But for some reason it just doesn't sound right!! I don't need the the extra torque, I am just using it for turning the crank on a giant Jack in the box!! Overkill I know but the crank is 3/8 steel rod with a heavy wood handle. I just want to make sure it will last a long time with no problems!! Again thanks for the replies!! Ordering a wiper motor now!! HH
If you could cut down on the weight or make the crank out of PVC and painted it to look like wood you could use a 5rpm Synchronous Motors

That is what I used for my 4ft J in B . Cost would be around $5 but it would not handle the weight of metal and real wood
 

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A motor that is designed for a certain voltage will be weaker if the voltage is lower, doesn't matter how many amps you put to it. Perfect example, your car battery and starter. The starter is designed for 12v, if your battery drops to about 11v, you ain't gonna start the engine even though the battery probably has way more amps than would be needed at 12v.
A typical car battery has a standing, no load voltage of 12.6v. When you apply the load, the voltage typically drops as low as 9.6v, drawing the current needed to start. A motor requires a high current draw on start-up. If only voltage was a consideration for starting a car, than you should be able to take 8 D sized batteries to start your car with. A standing voltage is a consideration for a bad battery, anything below 12v puts it at risk, but a cranking voltage drop test is more indicative of a battery failure. Also testing it with a full load.
 

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A typical car battery has a standing, no load voltage of 12.6v. When you apply the load, the voltage typically drops as low as 9.6v, drawing the current needed to start. A motor requires a high current draw on start-up. If only voltage was a consideration for starting a car, than you should be able to take 8 D sized batteries to start your car with. A standing voltage is a consideration for a bad battery, anything below 12v puts it at risk, but a cranking voltage drop test is more indicative of a battery failure. Also testing it with a full load.
No where did I say that amperage was not a factor.
Voltage and amperage both play a role for a motor to operate at a specified torque. If you drop the voltage below what the motor is designed for, the stall torque of that motor will be less no matter how many amps you throw at it, that's a fact, it's Ohm's Law. Current = Voltage ÷ Resistance. A stalled motor is nothing more than a big resistor at a fixed value. If you drop the supplied voltage, the current draw will be less which equates to less stall torque.
 

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Everyone assumes that more torque will allow you to lift a heavier load and that is not true. The amount you can lift is proportional to the power supplied to lift it. You need more power to lift something heavier and less power for something lighter. Power = speed x torque. Speed is proportional to volts and torque is proportional to current or Amps. So Power = volts times amps. So if you have a 12V/5A power supply the power is 60 and a 5V/5A power supply the power is 25.

I have taken and tried to lift a heavy load with a PC power supply and wiper motor and the 5V will lift a bit and then stall out. So I connect it to the 12V.....twice the voltage should lift it right? Not a chance and here is why.

PC power.jpg

By the image above I have 12V @19A = 228 and 5V @ 55A = 275

Hence less power In = Less power out.

Look at it like a lever arm with a fulcrum The load to lift is constant. The voltage is the fulcrum, closer to the load is higher voltage or speed, the weight applied to the other end is the current or amps. If the fulcrum is closer to the load then the lever arm is longer meaning you need less eight to lift the load. If the fulcrum is closer to the weight the lever arm is shorter, so you need more weight to lift the load.
 

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Everyone assumes that more torque will allow you to lift a heavier load and that is not true.
Not sure of the point you're trying to make.
Torque is a measurement of rotational force, so all else being equal, more torque would move a heavier load.
 
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