# DC motor. Calculate the current

• gucci
How much voltage is left for the coil ?In summary, the conversation discusses the calculation of current in a DC motor with a coil resistance of 2.0 ohms, powered by a 12 V battery with an internal resistance of 0.5 ohms. It is stated that the current at start-up is 24 A, and the question asks for help with calculating the current at 600 RPM when there is a counter EMF of 10 V in the coil. The solution involves considering the voltage drop across the internal resistance of the battery and the remaining voltage for the coil.
gucci

## Homework Statement

The coil of a DC motor has a resistance of 2.0 ohms. The motor is runned by a battery of 12 V and an internal resistance of 0.5 ohms.
a) Calculate the current at the moment the motor is started
b) Calculate the current when the motor is running at 600 RPM , when there is an induced counter EMF of 10 V in the coil.

I = E / R

## The Attempt at a Solution

a) is already solved I = 24 A

help with b), please

If you know the voltage from the internals of the battery and the voltage over the coil, what does the internal resistance of the battery see ?

## 1. How does a DC motor work?

A DC motor uses electromagnetic principles to convert electrical energy into mechanical energy. When an electrical current is passed through the motor's coils, it creates a magnetic field that interacts with permanent magnets to generate rotational motion.

## 2. What factors affect the current in a DC motor?

The current in a DC motor is affected by the voltage applied, the resistance of the motor's coils, and the load or torque on the motor. Increasing the voltage or decreasing resistance will increase the current, while increasing the load will decrease the current.

## 3. How do you calculate the current in a DC motor?

To calculate the current in a DC motor, you can use the formula I = V/R, where I is the current in amps, V is the voltage applied, and R is the resistance of the motor's coils. You can also use a multimeter to directly measure the current.

## 4. Why is the current important in a DC motor?

The current is important in a DC motor because it determines the amount of torque produced by the motor. A higher current will result in a stronger magnetic field and therefore more torque, while a lower current will result in less torque and potentially slower speed.

## 5. What are some common applications of DC motors?

DC motors are commonly used in a variety of applications, including electric vehicles, robotics, industrial machinery, and household appliances. They are also used in small electronic devices, such as fans and power tools, due to their compact size and efficiency.

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