Electric motors are used in various applications, from automobiles and power tools to portable fans. Electric motors can be powered by either AC or DC electricity, depending on what the application requires. Electric motors come in different sizes and styles, but their fundamental operation is similar: they convert electrical energy into mechanical energy through electromagnetic induction.
Electric motor performance varies based on the design and application; some factors include horsepower (HP), voltage (V), and RPMs (RPM). The following sections will explore how electric motor performance is affected by these three factors.
Horsepower’s (HP) Impact on Motor Performance and Uses
Horsepower is a measurement of power based on work output. Electric motors are rated by horsepower, giving consumers an idea of the motor’s capabilities. Electric motors are also measured in watts (W), which measures power over time, i.e., how much energy the motor will use while operating under certain conditions. Electric motors are typically designed to work at a specific voltage; by increasing the voltage, electric motor performance increases.
Electric motors have a maximum rated operating voltage that you should not exceed. Electric motors can perform better than their rating as long as the voltage is kept within a safe range. If an electric motor is operated with too high a voltage, it will overheat and can be permanently damaged.
Torque vs. Horsepower
The relationship between an electric motor’s horsepower and torque is that, for a given electric motor design, increasing the voltage or RPMs will increase HP (horsepower). Still, it will not increase the maximum torque of the machine.
Electric motors come with their maximum horsepower and torque listed on their specs; by changing these values, you can impact the overall performance of any electric motor.
Voltage’s Impact on Electric Motor Performance and Uses
Depending on whether an electric motor is AC or DC, certain voltages will cause the motor to operate more efficiently. Other factors include phase effects on amp draw and high and low voltages.
High and Low Voltage Effects
AC motors are typically designed to operate at 120 volts, but this varies depending on the manufacturer. As an example, electric power companies deliver electricity at around 120 volts AC for single-phase electric systems; higher voltages are used in three-phase electric systems.
You can operate electric motors designed to work at 120 V AC with 110 or 220 V AC without damaging the motor. Electric motors run more efficiently at around 120 volts AC, but they can be damaged if supplied with too low or too high of a voltage.
Voltage and Phase Effects on Amp Draw
The amp draw of an electric motor is the rate at which the motor uses amps, which measure electrical current flow. Electric motors are typically rated by their full load amps (FLA) or maximum amperage.
Electric motors are also measured in VA ratings: therefore, because the relationship between voltage and resistance is V = I * R, where V = voltage (in volts), I = current (in amps), and R = resistance (in ohms), by increasing the voltage you can increase the electric motor performance. For instance, electric motors designed to operate at 120 V will use more amps than if they were operated at 240 V; therefore, AC Electric Motor Performance is based on the highest voltage.
Voltage Impact on AC and DC Motors
DC motors are designed to operate at a certain voltage, but they can be damaged if supplied with too low or too high of a voltage. Electric motors are typically rated by their maximum operating voltage; electric motors are designed to operate between 90 and 180 volts DC. So, for example, you can use electric motors designed to work at 72 V DC with either 48 or 72 V DC without damaging them.
Electric motors will use more amps as the voltage increases. For example, electric motors designed to operate at 90 V DC will use fewer amps than if you run them at 180 V DC; therefore, DC Electric Motor Performance is based on the highest voltage.
RPM’s (Revolutions Per Minute) Impact on Motor Performance
RPMs can also impact motor performance. Here are a couple of variables:
Low RPMs will result in low torque. Electric motors designed to work at slow speeds can be operated with high RPMs without damaging the motor.
High RPMs will result in higher rotational force. As a result, electric motors designed to operate at high speeds can be used for low-speed uses without damaging the motor.
How RPM Relates to Torque
RPM impacts torque because torque is directly proportional to RPMs. Electric motors are designed to operate at certain speeds; therefore, if you increase the speed of the electric motor, you can increase the amount of torque that it generates. Electric motors are also measured in HP (HP) and voltage (V); therefore, you can estimate torque by combining the HP and voltage.
Electric Motor Search
Motors play a vital role in a variety of industrial applications. Simply put, they power many of the industrial machines we list. That’s where Surplus Record’s Electric Motor Search comes in. This powerful search tool allows you to search over 12,000+ motors for sale quickly and easily. You can narrow down your search further by filtering by horsepower, RPM, frame type, voltage, manufacturer, and even the type of motor.