A SureStep application showed repeatable stalling that increased when the drive current setting increased. The evidence establishes a current-dependent symptom, but it does not identify the drive model, supply voltage, motion profile, mechanical load, wiring, or root cause.
Observed SureStep stalling behavior
| Configuration | Drive setting | Observed result |
|---|---|---|
| STP-MTR-23079, rated 276 oz-in | 2.8 A/phase | Motor stalled |
| STP-MTR-34066, rated 434 oz-in | 2.8 A/phase | Stalling became more apparent |
| Installed configuration after accidental DIP-switch change | 1.2 A/phase | Stalling disappeared |
| Same configuration after restoring higher current | 2.8 A/phase | Stalling returned |
The repeatability makes drive-current selection a controlled diagnostic variable. It does not prove that excessive current alone caused the stall.
Why the torque increase does not identify the cause
Replacing the 276 oz-in motor with the 434 oz-in motor did not correct the problem. This means the available evidence does not support treating insufficient motor torque as the sole cause. The result could involve the drive configuration, motor-to-drive compatibility, wiring, supply behavior, motion profile, mechanical system, or another current-dependent condition; each remains a hypothesis until measured.
The DIP-switch interpretation is also unresolved. Confirm the switch pattern against documentation for the exact installed drive rather than assuming that the manual or the selected 2.8 A/phase setting is correct.
Controlled diagnostic procedure
- Record the exact drive model, motor model, supply, wiring arrangement, DIP-switch positions, commanded speed and acceleration, and mechanical load. These details are absent from the evidence but are required to isolate the cause.
- Use the repeatable 1.2 A/phase configuration as the baseline. Confirm that the motion completes without stalling under the same command and load.
- Change only the current selection to 2.8 A/phase. Repeat the identical motion and confirm whether the stall returns.
- Verify both switch patterns against the manual for the exact drive. Separately compare the selected current with the motor requirements; the evidence does not provide those requirements.
- If the result remains current-dependent, compare drive status, supply behavior, motor and drive heating, shaft motion, and mechanical loading during both tests. Do not change acceleration, speed, load, or wiring while comparing current settings.
Acceptance criteria
Accept a configuration only after it completes the required motion repeatedly at the actual load without stalling and its drive-current selection has been verified for the installed motor and drive. The successful 1.2 A/phase trial is evidence of operation in one test condition, not proof that this setting is valid for every duty cycle.
FAQ
Why does my SureStep motor stall more at 2.8 A/phase?
The evidence confirms that stalling returned at 2.8 A/phase and disappeared at 1.2 A/phase, but it does not establish the mechanism. Verify the exact drive DIP-switch table and motor-current requirements, then repeat the same motion while changing only current.
Will replacing an STP-MTR-23079 with an STP-MTR-34066 stop stalling?
Not in the documented case: replacing the 276 oz-in STP-MTR-23079 with the 434 oz-in STP-MTR-34066 made the stalling more apparent. Diagnose the drive configuration and application conditions instead of assuming higher rated torque will solve the fault.
Can I leave the SureStep drive set to 1.2 A/phase?
Only after verifying that 1.2 A/phase is valid for the exact motor and drive and testing the required load and motion profile. The evidence shows that this setting stopped the observed stall, but it does not provide enough information to approve it for the complete application.