Understanding Voltage Rating for Electro-Mechanical Solenoids in Robotics

[abs_vicky]

I m designing an electro-mechanical solenoid as the shooting mechanism in a robot. Its input is DC current. But, my guide asks me to mention its voltage rating. What is this and how to find it out?

 

[Fish4Fun]

Hrmmm, I am prolly going out on a limb here, but aren't all solenoids "electro-mechanical"? The purpose of a solenoid is to generate linear mechanical force from an electric current.

That aside, E = L di/dt . This implies that a change in current has a corresponding change in Voltage. The faster the current changes, the higher the voltage, and the higher the voltage, the faster the current changes.

All real-world, non-superconductor inductors have some resistance. The voltage rating is typically the constant voltage that produces the rated current. In practice the applied voltage is considerably higher than the "rated voltage" to achieve the rated current in a shorter period of time. The rated current is then maintained via PWM or some other current limiting scheme.

So, if your coil has a resistance of 5 ohms and a current rating of 1 amp, then the voltage rating is 5V. You would typically apply >20V to the coil for some period of time ( this figure is actually dependent on the coil's inductance) and then you would use some current limiting scheme for the remainder of the conduction period.

At least this is my impression of "voltage rating" with respect to an inductor. I am sure others will correct me if I have this wrong.

Fish