Oriental Motor Stepping Motor Systems Q&A

Submitted by Automation Engineering Staff
Are there ways to keep stepping motor temperature down?
There are several ways:
  • Adjust the operating current (a margin of torque must be present, since lowering the current decreases the torque). This lowers heat generation during operation.Use the driver functions.
  • The Hold-Off and Automatic-Current Down functions decrease heat generation when the motor is stopped.
  • Install the motor on a metal plate with good sinking capabilities.

Is there any way to decrease vibration during step motor operation?
There are several ways:
  • If using 2-phase, switch to 5-phase. For the ultimate smoothness, use a 5-phase microstepping driver unit, such as a RK or CRK, to decrease vibration.Adjust the operating current.
  • Vibration can be decreased by decreasing the torque.
  • Use a geared motor. Geared motors decrease the translation of vibration.Use a clean damper.
  • Vibration is absorbed by internal inert bodies and silicon gel.

What is the replacement for your older PH 2-phase stepping motors?
The PH Series has been replaced with the newer PK Series motors, which provide higher torque.

What is the step angle for your PK 2-phase stepping motors?
PK motors come in two basic step angles: Standard (1.8º/step) and high-resolution (0.9º/step). The high-resolution type is indicated by an "M" in the part number.

Does Oriental Motor have a standard driver for use with its 2-phase stepping motors?
No. Different motors have different back EMF values and therefore have different requirements to operate properly. The 2-Phase Stepping Motors section of our General Catalog lists the various AC or DC drivers which have been optimized to drive some of our 2-phase motors. These are available as a unit package (motor and driver together). The other motors do not have a recommended corresponding driver. In those cases you will need to supply your own suitable driver.

At how high a temperature can stepping motors be used?
The permissible temperature for the coils is 266°F (130°C), since the insulation of the motor is Class B. The motor can be used if the motor surface temperature is 212°F (100°C) or less. Try to use the motor at the lowest temperature possible and mount it to a metal plate that is a good heat conductor, since heat does affect the life of the motors ball bearings. Type A insulation 221°F (105°C) is a UL/CSA certification condition. When applying for UL/CSA certification as a set, use with a motor case surface temperature no higher than 167°F (75°C).

Why does the motor move a little when the power is turned on?
The rotor of the motor has 50 teeth and there are 50 locations where it can stop with stability. Depending on where the rotor has stopped before the power is turned on, it may move up to 3.6°.

Is it alright to machine the motor shaft?
When the shaft is machined, some impact may be felt by the ball bearings within the motor. Therefore, machining is not recommended. On a similar note, do not disassemble the motor. (Disassembling the motor will not only dramatically lower performance, it can also cause it to cease functioning if foreign matter gets inside.)

How far apart can the driver and controller (pulse generator) be?
Oriental Motor drivers use photocouplers that are resistant to the effects of external noise, so they may be separated up to approximately 6.6 feet (2m). When wiring is involved, always use either twisted pair wire (0.008 inch 2 [0.2mm 2 ] or larger) or shielded wire for connections and keep it as far away as possible from noise sources.

What are the differences in performance and wiring between Unipolar & Bi-Polar configurations?
Refer to the Unipolar/Bipolar Connection Diagram.

What is the difference between half-stepping a std. 2-phase motor and full-stepping a high-resolution type motor?
There is no difference in step angle. However, in half-stepping every other step has a smaller torque vector than the 2 adjacent ones. Depending on whether you land on one of the smaller vectors, you can have less holding torque. Full stepping has the maximum torque vector at all positions. 

How do stepper motors perform in very hot environments?
We recommend a maximum ambient temperature of ~50C.  For extreme cases, please consult our Tech Support Center 1-800-922-6646.

What is the difference between a high-resolution motor and standard 2-phase motor?
A standard 2-phase motor has 50 rotor teeth (1.8°/step) whereas the high-resolution type has 100 rotor teeth (0.9°/step). This type motor is preferred to reduce vibration of increase the positioning accuracy.

What is the difference between resolution and accuracy?
Resolution is based on the degrees of motion per step. Accuracy is dependent on the mechanical precision of the stator and rotor teeth and the winding balance. Error is non-cumulative.

Will a line-driver pulse output work with Oriental motor driver?
In most cases it works with connecting + Pulse out of the controller to + Pulse input of the driver and - Pulse out of the controller to – Pulse input of the driver. If the voltage level of + pulse out of the controller is higher than 3v, connect it to + Pulse input of the driver, and connect – Pulse out of the controller and – Pulse input of the driver to the Ground.

Can I use one sensor to home with your controllers?
Yes. For the Alphastep Plus controller, you will need to set HOMETYP = 4 (3 sensor mode). For the EMP controller, you will also need to set SEN = 3 (3 sensor mode). Connect your home sensor to the HOMELS input, and make sure you set the right direction to home.