Which DC motor is constant torque?
If we use armature voltage control with a fixed field excitation, our DC motor will develop the rated torque at the rated armature current independent of speed, this is usually referred to as constant torque operation. The speed will be proportional to armature voltage.
What is constant torque and constant power of DC motor?
Constant torque control is achieved below the base speed while the power increases linearly; the maximum power is acquired when the speed reached the base speed; then the torque starts to decrease to keep the power at its maximum value.
How do you find the torque constant of a DC motor?
The Torque Constant defines the torque-current relationship of a motor and is in Nm/amp. The motor and torque constants are related by the formula Km = Kt(trap)/sqrt(R), where R is the phase-to-phase resistance of the winding.
Do motors have constant torque?
Since the motor torque is proportional to current, the motor torque is constant (at its maximum) for that portion of the acceleration event. But after base speed is reached and exceeded, the motor torque reduces.
How is the starting and stall torque determined?
When there is no rotation in the motor, the wound coils are acting as a fixed resistance. Ohm’s Law states that current is equal to the supplied voltage divided by the resistance. This would be the starting/stall current. If the motor’s torque constant (K t) is known you can take K t * the current and determine the starting/stall torque.
What kind of motors work for constant torque?
Your simplest solution would be to control a motor with some sort of electronic drive and a feedback system. Most VFDs can operate in constant torque mode, and do so using the current measurement intrinsic to their design. Similarly most DC drives if you have a DC motor.
Can a VFD operate in constant torque mode?
Most VFDs can operate in constant torque mode, and do so using the current measurement intrinsic to their design. Similarly most DC drives if you have a DC motor. Stepper motors are trickier, since they are basically petitioners, with stepwise torque. As you have discovered they may need gearboxes.
Are there any types of DC motors that self lock themselves?
You can find one here at Servo city or try to DIY with hardware store threaded rod and an off the shelf gear. Another suggestion is a ratchet and pawl mechanism that may be easier to DIY than a worm drive and much cheaper than purchasing it.