{"id":3493,"date":"2026-06-16T12:28:19","date_gmt":"2026-06-16T10:28:19","guid":{"rendered":"https:\/\/www.rocketronics.de\/en\/?page_id=3493"},"modified":"2026-06-16T12:28:19","modified_gmt":"2026-06-16T10:28:19","slug":"jmc-faq","status":"publish","type":"page","link":"https:\/\/www.rocketronics.de\/en\/products\/jmc\/jmc-faq\/","title":{"rendered":"JMC Motors \u2013 Frequently Asked Questions (FAQ)"},"content":{"rendered":"\r\n\r\n
\r\n\r\n
\r\n

Frequently Asked Questions about JMC Motors (FAQ)<\/h1>\r\n

The most important questions about JMC servo and closed-loop motors \u2013 answered concisely.<\/p>\r\n <\/section>\r\n\r\n

\r\n\r\n

What does “integrated driver” mean?<\/h2>\r\n

With JMC iHSS and iHSV motors the power stage or servo controller is already built into the motor housing. You don’t need a separate driver in the control cabinet \u2013 only a supply voltage and a step\/dir control signal.<\/p>\r\n\r\n

Servo or closed-loop stepper motor \u2013 which is better?<\/h2>\r\n

Neither is generally “better”; they have different strengths. The closed-loop stepper motor delivers high torque at low speed, runs very smoothly and is cheaper \u2013 ideal for standard CNC routers. The servo motor spins higher, is more dynamic and maintains its torque across a wider speed range \u2013 ideal for fast or continuously loaded systems.<\/p>\r\n\r\n

Do JMC motors lose steps?<\/h2>\r\n

No. Both series work with encoder feedback. Position deviations are detected and corrected immediately, so no steps are lost \u2013 a key advantage over open-loop stepper motors.<\/p>\r\n\r\n

Which CNC controllers are the motors compatible with?<\/h2>\r\n

With all controllers that output a 5 V step\/dir signal \u2013 including Estlcam terminal adapters, Eding CNC, CSMIO, Beamicon-based systems and many others. The motors are controller-independent.<\/p>\r\n\r\n

Which power supply do I need?<\/h2>\r\n

One that delivers the motor’s nominal voltage (24\/36\/48\/72 V) and covers the combined current of the simultaneously accelerating axes with reserve. For servo motors a charge capacitor is additionally recommended to buffer regenerative spikes.<\/p>\r\n\r\n

When do I need the brake variant?<\/h2>\r\n

Whenever a vertical axis (typically the Z axis) must not drop on power failure. The models with holding brake carry the suffix “-SC” in the model name.<\/p>\r\n\r\n

Can I parameterise the motors?<\/h2>\r\n

Yes, many models can be adjusted via RS232 (e.g. current, microstep resolution). For this you need a USB-RS232 converter and the matching cable. Out of the box the motors are already sensibly preconfigured.<\/p>\r\n\r\n

Which frame size fits my machine?<\/h2>\r\n

That depends on weight, feed forces and mechanics. A structured decision aid is provided by our selection guide<\/a>.<\/p>\r\n\r\n

Are the motors available from stock?<\/h2>\r\n

Usually yes. You can see the current stock and prices directly on the respective product page in the shop<\/a>.<\/p>\r\n\r\n\r\n

What do the abbreviations iHSS, iHSSC and the suffix -SC mean?<\/h2>\r\n

“iHSS” stands for the closed-loop stepper motor series. An additional “C” (iHSSC) marks models with integrated reverse-polarity protection on the supply voltage. The suffix “-SC” on the model name means the motor additionally has an integrated holding brake. For the servo motors the same applies analogously with “iHSV” or “iHSVC”; the brake variant also carries the suffix “-SC”.<\/p>\r\n\r\n

What is the benefit of the reverse-polarity protection on iHSSC models?<\/h2>\r\n

If the supply voltage is accidentally connected the wrong way round (reversed polarity), this circuit protects the motor electronics from damage. This is a valuable safety plus, especially during initial commissioning and in service cases.<\/p>\r\n\r\n

Which voltage should I choose?<\/h2>\r\n

Within the permissible range the rule is: a higher supply voltage improves the usable torque at higher speeds. For the smaller frame sizes 24\u201336 V are recommended, for the NEMA34 models 60\u201380 V. Always stay within the limits stated in the datasheet.<\/p>\r\n\r\n

Do the motors get hot?<\/h2>\r\n

Closed-loop stepper motors only draw as much current as is currently needed and therefore stay considerably cooler than classic stepper motors, which are permanently energised at rated current. A certain amount of warming during operation is normal and harmless. Optional covers additionally protect the motors from chips and dust.<\/p>\r\n\r\n

Do I need a charge capacitor?<\/h2>\r\n

For servo motors a charge capacitor is recommended, since decelerating servos feed energy back into the power supply and can thus briefly raise the voltage. The capacitor module buffers these spikes and protects the power supply and motor electronics. For pure closed-loop setups it is usually not strictly necessary.<\/p>\r\n\r\n <\/section>\r\n\r\n

\r\n

Question Not Covered?<\/h2>\r\n

We are happy to help \u2013 and the motors are ready to ship in the shop.<\/p>\r\n

Back to the JMC overview<\/a><\/p>\r\n <\/section>\r\n\r\n<\/div>\r\n\r\n\r\n\r\n