Can Reversible Motors Only be Used for 30 Minutes?
It’s hot today! I'm so happy to be in a haunted house with Ms. Ori.
Don't be so frightened and buckle at the knees!
Ahh!!! Oh, I'm surprised. Hey, if you look closely at this ghost doll, you'll see that it uses a reversible motor!
Oh my, you really know your stuff.
Ah! But it's hot to touch! Maybe it's because it's been moving for a while?
Mr. Vex! Can you explain what kind of motor is a reversible motor?
Of course! Reversible motors are suitable for instantaneously switching the rotation direction and intermittent operation applications that repeatedly start and stop, right?
Yes, you're learning a lot!
Hehehe! …By the way, the catalog says that reversible motors have a "30 minutes rating." Does that mean I can only use it for 30 minutes?
That's right. A reversible motor, like an induction motor, is limited to 30 minutes of uni-directional continuous operation.
Why is that?
It has to do with the characteristics of reversible motors. Reversible motors are designed to allow you to instantly switch the rotation direction. Therefore, the operating current is higher than the induction motor, and that's why the temperature rise is larger. That's why Oriental Motor sets the continuous operation time as "30 minutes."
I see, so that's what you meant.
But you see, if you can keep the temperature rise low, the operating time will change. As a reference, if the motor's case temperature is max. 90˚, it can operate for 30 minutes or more. But even though the case temperature is 90˚, the lifetime varies depending on the temperature, so it's better to use it at the lowest temperature as possible.
I see. So what's the best way to keep the temperature of the motor low?
The temperature of the motor will vary depending on the load, operating cycles, the way the motor is mounted, ambient temperature, and various of other conditions. So you can keep the temperature rise low by forced cooling of the motor, installing a heat sink, or stopping the motor for a longer period of time by natural cooling.
I see, I've got it!! I know the reversible motor has a "30 minutes rating," but if you're careful about the motor's case temperature, you can run it longer than 30 minutes in a variety of operating patterns!(*) I've learned a lot.
Ah! Vex!
…!! Ah!
*For information on operating patterns, please refer to the technical reference.
