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### Author Topic: What's the difference between stepper and servos?  (Read 5332 times)

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#### jbrs128

• Guest
##### What's the difference between stepper and servos?
« on: March 29, 2008, 08:29:53 AM »
What exactly are those two? What is best, accurate and fast and actually how it works? Is there really a difference?

#### Andre

• Guest
##### Re: What's the difference between stepper and servos?
« Reply #1 on: March 31, 2008, 22:39:43 PM »
Absolutely different.

Servos:
Servos work in a loop, using feedback. A servo is controlled by a drive. This motor has an encoder attached to it's shaft (either internal or external). This encoder sends a signal to the drive about the revolutions of the motor shaft. So you can "say" to the drive "Ok, i want 150 revolutions of the motor with this acceleration and at this speed" and it will be done, by changing the frequency and the amplitude of the power. Very sophisticated, with good accuracy, great speed and acceleration management and not at all cheap

Stepper:
Much more simple as operation, more complicated motor. The motor is divided into steps. Each revolution for example may have 180 steps of 360, or less, 90. Depends of the type of the motor. The motor then can accept pulses and each time it revolves for 1/360 or 1/180 or according to it's specifications. Significantly slower from the servo. It has a standard accuracy that can not be higher or lower. In conjunction with a power screw or corona - pinion it can produce some good torque but it will never be smooth as it rotates by steps and not like servos. All the disadvantages disappears in a flash as this kind of motors are EXTREMELY cheaper than servos. So cheap, that i bought 5 of them without really knowing what to do them. (I still do not have a servo bought  and guess why...)

#### jbrs128

• Guest
##### Re: What's the difference between stepper and servos?
« Reply #2 on: April 02, 2008, 00:16:38 AM »
Thanks a lot Andre.

#### Andre

• Guest
##### Re: What's the difference between stepper and servos?
« Reply #3 on: April 06, 2008, 13:29:30 PM »
anytime mate

#### spic0m

• Global Moderator
• Hero Member
• Posts: 841
##### Re: What's the difference between stepper and servos?
« Reply #4 on: April 06, 2008, 16:51:30 PM »
Move this to mechanics board