# What determines the method of controlling motor speed?

Contents

## What are the factors that controls motor speed?

Thus, there are three general methods of speed control of D.C. Motors.

• Resistance variation in the armature circuit: This method is called armature resistance control or Rheostat control.
• Variation of field flux Ф This method is called field flux control.
• Variation of the applied voltage.

## What controls the speed of a motor by controlling frequency?

A variable frequency drive controls the motor speed by using PWM (Pulse Width Modulation) to alter the power supply frequency that’s fed to the motor. There is typically no feedback coming back from the motor; although some drives uses back EMF as feedback.

## Which of the following method is used to control motor speed control?

Explanation: In field control method we change the flux produced by machine with the help of field current. If applied voltage is changed, definitely speed will change. By adding resistance in series with armature voltage of the armature can be varied to change the speed.

## How does a motor speed control work?

How does a motor speed controller work? All 4QD controllers work by switching the battery connection to the motor on and off around 20,000 times a second using a technique called pulse width modulation [PWM]. … The motor averages these pulses out, as this rate of switching is too fast for the motor to detect.

## Which is a better method to control motor speed Mcq?

DC Motor Speed Control MCQ Question 1 Detailed Solution

We can control the speed by increasing armature resistance. This method gives only below base speeds. This method is a constant torque and variable power drive.

## Which method is suitable for the speed control below and above the normal rated speed of DC shunt motor?

Voltage control method is suitable for speed control, below and above normal rated speed of d.c. shunt motor. Q.

## How do you reduce motor speed?

So, if you want to decrease speed, decrease voltage. If you want to decrease torque, decrease current. If you increase torque (say by putting a brake on the motor), you are increasing motor torque. But if you don’t change the supply of electrical power, then the mechanical power also won’t change.

## How do you control speed of electric motor?

Thus, the speed of a DC motor can be controlled in three ways:

1. By varying the supply voltage.
2. By varying the flux, and by varying the current through the field winding.
3. By varying the armature voltage, and by varying the armature resistance.

## How do you control the speed of a synchronous motor?

Speed of synchronous motors can be controlled using two methods called open loop and close loop control. Open loop contol is the simplest scalar control method where motor speed is controlled by independent frequency control of the converter.

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## Which method can be used to obtain speed greater than the rated speed of the motor?

By varying flux, we can increase the speed more than its base speed. This method is constant power and variable torque drive.

## Which method is used to obtain speed control above rated speed?

Speed control of DC Shunt Motor

The flux of DC motor can be varied by varying Ish (shunt field current), with a rheostat in series with shunt field. As Ish in shunt motors is relatively small, Cu losses are also small. Thus this method is efficient for DC shunt motors. This method gives speeds above rated speed.

## Which of the following speed control method reduces the DC motor efficiency?

Application: As the armature resistance control method involves additional resistance in series with armature resistance, the power losses are high. Thus, efficiency is minimum in this case.

## What are the different methods of speed control of induction motor?

Speed Control Methods of Induction Motor:

• Control From Stator Side:
• Control From Rotor Side:
• Speed Control by frequency variation:
• Speed Control By Pole Changing:
• Speed control by varying Supply voltage:
• Speed control by varying Rotor Resistance:
• Speed control by injected EMF:
• Speed control by Cascade Connection: