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Detent torque is the amount of torque (the measured ability of a rotating element, as of a gear or shaft, to overcome turning resistance), that must be applied to overcome the static equilibrium of the motor when it is in an state of rest and unpowered.
What is the difference between holding and detent torque?
Holding torque is typically higher than running torque, and is limited primarily by the maximum current the motor can withstand. From a practical standpoint, holding torque is the sum of the magnetic force exerted by the coils to hold the motor’s current position, plus the detent torque.
What causes detent torque?
The detent torque exists because of the residual magnetism in the permanent magnetic material used for the construction of the rotor of the motor. It is produced when the stator coils are not energized. This torque prevents the rotor from drifting when the motor supply is turned off.
How is detent torque calculated?
Detent torque is calculated as the differential of the magnetic coenergy with respect to rotor angular position at constant rotor excitation. Validation of the detent torque equation is performed by comparing results obtained from the proposed method with laboratory test results.
Which torque is high in stepper motor?
This is referred to as the motor’s holding torque and is the torque required to move the motor one full step when the coils are energized but the rotor is stationary. A stepper motor’s holding torque is higher than its running torque and is limited primarily by the amount of current the motor can withstand.
What is maximum holding torque?
The stepper motor holding torque refers to the maximum torque that the stepper motor can output when the motor’s phase windings pass the rated current and is in the static lock state. It is one of the most important parameters of a stepper motor.
How much holding torque do I need?
Holding torque is not usable torque and should be approximately halved if operating torque is not given. Ultimately the amount of torque depends on how much power (like watts power) you’re pumping into your steppers.
How do you reduce cogging torque?
The most effective way to reduce cogging torque is skewing of stator slots or rotor poles. It means skewing of one side of stator (rotor) core by few degrees in according to the other side of core (Fig. 7). The skewing allows to eliminate the cogging torque or to reduce it to minimum.
What is the effect of cogging torque?
The effect of cogging torque decreases the accuracy of the motor positioning at low speed, produces additional friction resistance, and to some extent, reduces the output power if the axial flux machine is applied as an electrical generator [8,9,10].
What is holding torque of motor?
If external force is applied to a stepping motor when it is stopped but energized, the attractive force generated between the rotor and stator works to maintain the stop position of the motor. This torque of withstanding the external force is called the holding torque.
What is holding torque in epicyclic gear train?
It is a motorized unit consisting of SUN gear mounted on input shaft. Two plane gears mesh with the annular gear. These planet gears are mounted on a common arm to which output shaft is fitted.
Do servo motors have holding torque?
Unlike stepper motors, they do not have holding torque per se. The combination of speed and torque enables servo motors to deliver better acceleration than stepper motors. They also deliver improved positioning accuracy as a result of closed-loop operation.
Do DC motors have holding torque?
Normal DC motors and servo motors do not have much torque at low speeds. Suitable for applications with high holding torque. Stepper motors can be easily controlled with microcontrollers such as the ATmega chips that are readily available on Arduino development boards.
Why do stepper motors have high torque?
Why do stepper motors have trouble producing high torque at high speeds? For a given stepper motor design, torque production is primarily a function of current through the motor windings — the higher the current, the more torque the motor produces.
How does a stepper motor run at high speed?
There are a few main ways to increase your maximum step speed: Use a higher voltage. Set the current limit to the maximum allowed by your stepper motor. Ramp the stepper speed up slowly. Decrease the external load on the stepper.
How do you increase holding torque?
Ultra-high-torque step motors are another way of effectively increasing torque within a given frame size. They can boost holding torque by 25 to 45% in a stepper motor identical in size to a conventional motor.
Is stall torque the max torque?
Stall torque is the maximum torque that can be applied to the shaft and cause the motor to stop rotating.
What is torque speed curve?
The torque speed curve of a load is a plot showing its torque requirement on the y- axis versus the speed on x-axis. It’s the torque requirement of the load from zero speed to full speed. Its application/load specific and varies with different load types. These are also called as constant torque loads or applications.
How do I calculate torque?
A practical way to calculate the magnitude of the torque is to first determine the lever arm and then multiply it times the applied force. The lever arm is the perpendicular distance from the axis of rotation to the line of action of the force. and the magnitude of the torque is τ = N m.
How is motor torque calculated?
Torque (lb.in) = 63,025 x Power (HP) / Speed (RPM) Power (HP) = Torque (lb.in) x Speed (RPM) / 63,025. Torque (N.m) = 9.5488 x Power (kW) / Speed (RPM) Power (kW) = Torque (N.m) x Speed (RPM) / 9.5488.
What is torque to weight ratio?
Definition: The ratio of torque to the weight of the moving part of an instrument is known as a torque/weight ratio. It indexes the performance of the instrument. The high value of the torque-weight ratio shows that even for the small value of deflecting torque, the pointer deflects and shows the measured value.
