# Tagged Questions

185 views

### How to fix servo motor broken by wrong polarity [closed]

I accidentally plugged in my servo with the wrong polarity (with the order of wires being signal, ground and power). It immediately started releasing the 'magic smoke', but I managed to unplug it ...
186 views

### Electric engine power over RPM

I have started to research about electrical motors and batteries. I have learned physics in high school and I understand electricity. My question is whether an engine's power depends on its RPM or ...
123 views

### Regulating Voltage at High Current

I am using a 12 V power supply to run a series of motors in Parallel expecting them to pull up to 25 ampere. The motors are running too fast at 12 V so we need to drop it down to 9 or 10 V, preferably ...
97 views

### How to trade off connection styes in mixed gnd systems( power gnd and signal gnd)?

I am using a motor driver L6235 from ST:application note.On page 6, it gives me a layout suggestion: it says that the SIGNAL GND and POWER GND should be connected in a single point: the negative ...
206 views

### DC Motor Efficiency at Fixed Torque

I am in a muddle here, so thanks for making the effort to have a read. I understand that electrical power going into motor is given by: $P_e=I^2R$ I understand that mechanical power out is given ...
157 views

### What is the function of a capacitor in a motor circuit?

I read a manual of how to connect a speed controller to a motor. I see there is a capacitor as shown below. My question is what the function of the capacitor is? Thanks
357 views

### Maximum power for Arduino Monster Moto Shield

I'm reading the specs for the SparkFun Monster Moto shield which specifies that Max Voltage is 16V Maximum Current 30A Given Ohm's law, does that mean that the maximum power is 480 watts? That ...
348 views

### Does anyone build 100k RPM alternators?

What I'm contemplating is the practicality of building a direct drive turbine-alternator (or generator) system out of an engine something like this. Based on some reasonable guesses, that would take ...
279 views

### DC motor vs AC motor weight considerations

For a given power rating, does a permanent magnet DC motor have a weight advantage over either a three phase permanent magnet synchronous machine, or vice versa? Or does it work out that they would be ...
374 views

### Why are battery-powered appliances and tools specified in volts? [closed]

"Powered with a suction of 18 volts" Isn't this just a nonsensical "bigger is better" measure? The thing you really care about as a customer is the motor's torque or power or RPM or something ...
132 views

### Switching regulator to power motor

I am trying to power my servomotor only for a short period of time (controlled by my MCU). I have seen I could use a switching regulator (3 pins). The thing is that I am working with really low power. ...
228 views

### Electric Power Systems for a qudrocoper base on 30amp Speed Controller and NX-4008-620 - NX-4008-620kv Brushless motor

I'm in mood to put together my own quadrocopter. Just before I ordered parts wanted to some experts to tell me if configuration if compatible enough. Or maybe you have better suggestions for this ...
255 views

### Synchronous motor mystery

Not too long ago I acquired an old ('70/'80) German flip clock. I found out that this clock is driven by a one-phase synchronous engine. I can't get the motor to run. I (carefully!) connected the ...
145 views

### Circuitry for Running Many Small Motors

I'm creating a simple vibration mat for a child which will be triggered by a force sensor. I'm not trying to do anything complex (like changing frequency of vibration) - simply an on/off circuit. What ...
592 views

### how to control brushless dc servo motor?

I have one of this motor and would like to make a controller for it ( just a speed controller with regulator that change speed from zero to maximum. ). I know micro controller and embedded system, but ...
953 views

### how to read battery spec?

I window shopped for a small size battery. On the battery specifications, there are: capacity(mAh) : 85mAh Pulse Current(mA) : 190 Cycle Life(Times) : 300 What does Pulse Current mean? Does it ...