# Tag Info

### 12V fan drawing more current when connected to 24V power supply. Why?

Basically brushed motors act like capacitors. Connect a DC voltmeter parallel with your fan motor if you do not believe me. The easiest fix is probably to use another ADC channel to measure the motor ...
• 33.8k

### How to filter the ac signal in a dc cooling fan circuit

A simple low pass LC filter is the first thing that one might think of to reduce the supply current ripple in a circuit that draws current in pulses. Here is a model we can use to simulate such a ...
• 23.5k
1 vote

### How to filter the ac signal in a dc cooling fan circuit

Assuming there is nothing else powered by the same wires as the fan, a common mode filter should be effective at reducing both differential mode and common mode noise. https://ka7oei.blogspot.com/...
• 20.1k
1 vote

### How to filter the ac signal in a dc cooling fan circuit

What you need to filter those ripples is a Pi or a T filter (source of image): A simple capacitor is not enough. You need to have an inductor in series to create a low-pass filter. Choose the filter ...
• 1,631
1 vote

### Magnetic lines geometry inside a dc motor

In a production DC motor as you suggest the magnetic fields are perpendicular to each other in order to maximize the torque produced by the motor. They are kept this way during the rotation of the ...
• 10k
Accepted

### Par control in DC servomotor

The gear train is a confounding factor. You'll probably need to drive your servo through a torque sensor, and have a controller in the Arduino that backs the servo off when the torque reaches your ...
• 46.2k

### Converting DC motor's tachometer output to DC using bridge rectifier

A very long time ago I worked on daisywheel printers. These used optical encoders that put out a pair of quadrature sine waves, from which position and velocity were derived. The short summary is, the ...
• 54.1k

### Monster moto shield + Arduino +Pololu 12V, 29:1 Gear Motor Encoder hardware problem

PWM in the Arduino is 0 to 255. You have 0 to 1023, a 10 bit value, which is not an int value (in setup) either. If you want to control via a pot and read the value, 0 to 1024, just divide by 4 to get ...
1 vote

### Can I control a motor in both directions using two sets of dry contacts

This could be done with two SPDT relays: simulate this circuit – Schematic created using CircuitLab I used a lamp to represent the motor, as I couldn't find a motor in CircuitLab. With both ...
• 59.2k

### Can I control a motor in both directions using two sets of dry contacts

The usual way to do reversing is with an H-bridge, which takes four relays. If you're open to adding an additional part you can get an H-bridge IC and control that with your dry contacts. Your dry ...
• 349
Accepted

### Can I control a motor in both directions using two sets of dry contacts

The simplest way to do this with two dry contacts would be to use a DPCO relay to set direction, and control that with one dry contact. The other dry contact is used for on/off. Like this: Protection ...
• 7,052