The rotor has slightly fewer teeth than the stator, such that one "electrical rotation" (each coil being switched on in sequence) causes the rotor to advance by the number of missing teeth. That is what makes a stepper so precise; it gets 4+ divisions per tooth.
Equally pedantic: it functions as a linear stepper motor, therefore it is a stepper motor. That it doesn't have a platen is not relevant. Being a stepper is not a statement of precision, it is a matter of principle, does the movement occur in discrete steps or does it occur by continuous movement through a magnetic field? This is a stepper by any practical definition.
it is a matter of principle, does the movement occur in discrete steps or does it occur by continuous movement through a magnetic field?
motor typology is not well defined, so we're arguing a moot point. That said, I think this is a poor criterion for stepping. BLDCs, SRMs, and doubly-wound machines are all steppers by this definition. IMO it is not useful.
All motors which are called stepper motors have one unique thing in common: they take multiple electrical rotations per mechanical rotation. This motor does not do that.
If you can lock the movement into a specific position and it's repeatable because of the geometry of the motor, it's a stepper.
Yeah, of course it doesn't have the same design of the steppers you buy around. That's obvious from the title alone. That doesn't make it not a stepper. And yeah, it's less precise than the ones you can buy¹. That should be expected too.
1 - Although, that conclusion is way too simplistic to make. It has a different kind of imprecision, so depending on how you compare, you may as well conclude that it's more precise.
If you can lock the movement into a specific position and it's repeatable because of the geometry of the motor, it's a stepper.
BLDC, series wound, and switched reluctance motors will also hold their position. Cogging torque exists in the majority of motor types. It is not very useful for dividing motors into families, and is certainly not specific to the group of machines called stepper motors.
If you energize each coil of a BLDC, series wound, or SR motor (not the wires, each actual coil) in sequence, the shaft of the motor will rotate once (or very close to once). If you do the same with a stepper motor, the shaft will have turned 22.5 degrees or less.
It is possible to make a linear stepping motor. The Vernier scale is basically stepping as applied to measurement. This is not that.
Comments
Pedantic: this isn't a stepping motor, it's just a plain linear motor.
Stepper motors have multiple teeth per pole: https://en.wikipedia.org/wiki/Stepper_motor#/media/File:Step...
The rotor has slightly fewer teeth than the stator, such that one "electrical rotation" (each coil being switched on in sequence) causes the rotor to advance by the number of missing teeth. That is what makes a stepper so precise; it gets 4+ divisions per tooth.
Equally pedantic: it functions as a linear stepper motor, therefore it is a stepper motor. That it doesn't have a platen is not relevant. Being a stepper is not a statement of precision, it is a matter of principle, does the movement occur in discrete steps or does it occur by continuous movement through a magnetic field? This is a stepper by any practical definition.
motor typology is not well defined, so we're arguing a moot point. That said, I think this is a poor criterion for stepping. BLDCs, SRMs, and doubly-wound machines are all steppers by this definition. IMO it is not useful.
All motors which are called stepper motors have one unique thing in common: they take multiple electrical rotations per mechanical rotation. This motor does not do that.
You could make it move continuously by using an infinite number of microsteps.
The same holds for a rotating stepper.
If you can lock the movement into a specific position and it's repeatable because of the geometry of the motor, it's a stepper.
Yeah, of course it doesn't have the same design of the steppers you buy around. That's obvious from the title alone. That doesn't make it not a stepper. And yeah, it's less precise than the ones you can buy¹. That should be expected too.
1 - Although, that conclusion is way too simplistic to make. It has a different kind of imprecision, so depending on how you compare, you may as well conclude that it's more precise.
BLDC, series wound, and switched reluctance motors will also hold their position. Cogging torque exists in the majority of motor types. It is not very useful for dividing motors into families, and is certainly not specific to the group of machines called stepper motors.
If you energize each coil of a BLDC, series wound, or SR motor (not the wires, each actual coil) in sequence, the shaft of the motor will rotate once (or very close to once). If you do the same with a stepper motor, the shaft will have turned 22.5 degrees or less.
It is possible to make a linear stepping motor. The Vernier scale is basically stepping as applied to measurement. This is not that.
More pedantry: it's a PM (permanent magnet) stepper motor, whereas I think most common stepper motors are hybrid VR (variable reluctance) / PM type..