Table of Contents

- 1 What is the relationship between motor speed and voltage?
- 2 What is the relationship between voltage and RPM?
- 3 What is the relationship between a DC motor speed and its torque?
- 4 What determines speed of motor?
- 5 Is voltage directly proportional to speed?
- 6 What kind of relationship exists between the speed and armature voltage of a separately excited DC motor?
- 7 Why is torque and speed inversely proportional?
- 8 Does voltage affect motor speed?
- 9 Why does a 12V motor run slower than a 24V motor?
- 10 What is the relationship between torque and speed in a motor?

## What is the relationship between motor speed and voltage?

DC motors are relatively simple machines: when the load on the motor is constant, speed is proportional to supply voltage. And when supply voltage is constant, speed is inversely proportional to the load on the motor.

## What is the relationship between voltage and RPM?

Voltage is directly proportional to RPM.

**What is the relation between armature voltage and speed?**

In the armature control method, the speed of the DC motor is directly proportional to the back emf (Eb) and Eb = V- IaRa. When supply voltage (V) and armature resistance Ra are kept constant, the Speed is directly proportional to armature current (Ia).

### What is the relationship between a DC motor speed and its torque?

Torque is inversely proportional to speed. Thus, when speed increases, torque will decrease.

### What determines speed of motor?

The rotating speed of an electric motor depends on two factors: its physical construction, and the frequency (Hz) of the voltage supply. Electrical engineers select the speed of a motor based on the needs of each application, similar to how the mechanical load determines the horsepower required.

**What determines a motors voltage?**

An AC induction motor is designed around a specific ratio of voltage AND frequency because it has to do with the magnetic flux and the resulting strength of the magnetic fields. So if a motor is designed as 230V 60Hz, it is designed around the magnetic flux strength when you apply 3.833 Volts per Hertz (V/Hz).

## Is voltage directly proportional to speed?

The applied voltage equals the voltage drop across the coil resistance, R, and the inductor, L, plus the back-EMF. From the analysis above, we can see that when the load (torque) on the motor is constant, speed is directly proportional to supply voltage.

## What kind of relationship exists between the speed and armature voltage of a separately excited DC motor?

proportional

You have seen that the speed of a separately-excited dc motor is proportional to the armature voltage applied to the motor.

**Why does motor torque decrease with speed?**

The Reason that Torque and Speed are said to be inversely proportional is the ability to generate torque diminishes with increase speed. The reason for this is because the BackEMF opposes the supply that is attempting to force current into the stator, that will generate EM-Torque.

### Why is torque and speed inversely proportional?

This is because the torque is supplied by the current, while faster speeds increase the back emf which not only limits its final speed but blocks incoming current, therefore lowering torque. This is Why Torque and Speed are Inversely Proportional in an Electric Motor.

### Does voltage affect motor speed?

Back to the original question: how does voltage affect speed? From the analysis above, we can see that when the load (torque) on the motor is constant, speed is directly proportional to supply voltage. And, when the voltage remains constant, an increase in the load (torque) on the motor results in a decrease in speed.

**How does voltage affect the speed of a motor?**

From the analysis above, we can see that when the load (torque) on the motor is constant, speed is directly proportional to supply voltage. And, when the voltage remains constant, an increase in the load (torque) on the motor results in a decrease in speed.

## Why does a 12V motor run slower than a 24V motor?

If the battery is low and supplying less voltage, the speed will decrease accordingly. Now, if you connect that same 12 VDC motor into a 24 VDC power source, your speed typically doubles.

## What is the relationship between torque and speed in a motor?

From this we can see that the motor’s maximum speed occurs when there’s no load (torque) on the motor. Similarly, maximum torque occurs when angular velocity is zero. These two relationships can be seen in a typical DC motor’s torque-speed curve.

**How does a motor speed up or slow down?**

The motor either speeds up or slows down according to the load torque. It is ideal to size a motor properly so you can operate closer to maximum efficiency (rated torque and rated speed). Look at the speed-torque curve below for an AC induction motor.