Electric Motor information plate…

In earlier blogs we talked about Voltage and FLA’s (Full Load Amps) and how this information could be used in better operating an electric motor.

This entry is about Locked Rotor Amps.

Locked Rotor Amps are the amount of power that this motor will draw when it’s starting or when it’s attempting to start but cannot.

It might not start because the bearings have seized, for example.

An electric motor is considered “locked” any time the rotor isn’t rotating. If a start is attempted but the motor cannot for a mechanical reason rotate, the motor will be in locked rotor amp.

Therefore, the LRA (locked rotor amperage) of an electric motor is the maximum amount this motor will draw when it’s attempting to start, regardless of the condition of that motor.

 

What’s FLA on the motor info panel mean?

FLA is the acronym for “Full Load Amps”.

FLA is the current that this particular motor will draw when the load on the motor reaches it’s rated horsepower.

The motor will draw less than it’s FLA if the motor is loaded at less than it’s rated horsepower, and will draw more FLA’s when it’s loaded higher than it’s rated horsepower.

Measuring the amps a motor is drawing and comparing those to it’s FLA will quickly tell you if the motor is being overloaded in the application.
If you have a question about control panels, motor controls, industrial wiring, get help from a pro. Ask Jim!

Next blog we’ll look at Locked Rotor Amps.

 

What’s on an Electric Motor information plate?

Each electrical motor comes with an information plate. That plate provides details about the motor itself, and it’s optimum operating parameters.

Voltage
One of the boxes on the information plate is marked Voltage. The number in this box identifies the design voltage for that particular motor.

The electric motor may be operated safely at any voltage that is within plus or minus 10% of the number shown in the Voltage box.

Got an industrial electrical or machine control question? Ask Jim!

What’s FLA (Full Load Amps) mean? That’s for the next blog.

 

Motor Service Factor

An electrical motor has a Service Factor.

The number assigned to a motor indicates how much more work a motor can be expected to provide over and above it’s rated horsepower.

An SF (service factor) of 1.15 means that a 1 HP motor can do work up to 1.15 HP for a period of time.

The motor service factor should not be used in the installation, but rather, is a safety factor to be used when the load temporarily exceeds the nominal rating of that motor. Here’s more information.

 

What’s Tips in Controlling Machinery about?

There is a shortage, at least from my search perspective, of good industrial maintenance information in blogs and web sites.

This site addresses part of that by providing informative comments about machine controls, the hows, whys, and pitfalls of controlling industrial equipment using PLC’s and control panels.

You want to keep this blog on a feed for the information it will provide.