NIDEC 24H Series Positionable Brushless Motor
The NIDEC 24H series positionable brushless motor is essentially an all-in-one low-cost servo that integrates a brushless motor, encoder, driver IC, and microcontroller into a φ42 mm motor housing. Upstream commands are sent via pulse signals; downstream, the internal microcontroller executes closed-loop control of positioning, speed, and holding torque. The external interface is simple – only a 24V power supply plus a few logic signals are required. Therefore, it is often positioned as an upgrade replacement for stepper motors and a cost-effective alternative to traditional AC servos.
🎯 Product Positioning: Integrated Low-Cost Servo
The internal circuit board integrates sensors, an encoder, a motor driver IC, and a microcontroller, providing:
- Positioning function: Speed can be controlled by inputting pulse signals, enabling positioning and holding torque.
- Brushless advantages: Low power consumption, no step-out (loss of synchronization), instant start/reverse.
- Compact size: Lighter and smaller than stepper motors of equivalent power, facilitating resource saving and miniaturization.
NIDEC officially defines the 24H series as a "Compact high output positioning control motor," emphasizing small size, high output, high efficiency, low vibration/noise, and built-in positioning control. Its positioning control achieves step-less position accuracy that is difficult for stepper motors to attain. It is a highly integrated, low-cost servo motor.
🔌 Interface and Signal Definitions (12-pin Connector S12B-ZR-SM4A-TF)
| Pin | Name | Direction | Function Description |
|---|---|---|---|
| 1 | STMP | IN | Pulse input terminal (position command) |
| 2 | START | IN | Enable, active High: accepts STMP & CW/CCW when High; ignores when Low |
| 3 | 3.3V/5.0V | IN | Logic power, selectable 3.3V or 5.0V |
| 4 | CW/CCW | IN | Direction switch: CW = Low / CCW = High |
| 5 | READY | OUT | Status output: High = normal operation / Low = stop or fault |
| 6 | RESET_N | IN | Microcontroller reset, active Low |
| 7 | TOOLO | – | Leave open, no connection needed |
| 8 | ENCB | OUT | Encoder phase B |
| 9 | ENCA | OUT | Encoder phase A |
| 10 | SGND | IN | Signal ground |
| 11 | GND | IN | Power ground |
| 12 | VM | IN | 24V main power |
External requirements are simply: 24V main power (VM) + 3.3/5V logic power + STMP pulses + START enable + CW/CCW direction. This is a typical "pulse + direction" stepper-type command interface, but internally it executes brushless closed-loop servo algorithms.
⚙️ Control Timing Essentials
- On power-up, the microcontroller's RESET function activates.
- Pulse input is only effective after the START signal has been held High for at least 1 ms (pulses before START goes High are ignored).
- When the motor is in the START state but no pulse is input, it automatically enters holding torque (brake) mode.
- STMP pulse conditions: frequency ≤ 20 kHz, High level ≥ 5 μs.
- Recommended acceleration/deceleration time for start/stop: 100 ms.
- Rotation accuracy degrades below 500 rpm.
📊 Performance Specifications (24H Series)
Three power versions, all with φ42 mm diameter:
- 24H-10W: Output power 10W class (max output 18W)
- 24H-20W: Output power 20W class (max output 30W)
- 24H-20W (High Torque version) (max output 14W)
Body length: 34 mm (10W) / 43 mm (20W)
Encoder: 400 ppr, positioning accuracy ±0.9°
Speed range: 0–4000 rpm
🛡️ Protection Functions and Fault Recovery
Under any of the following conditions, the internal system detects a fault and stops the motor:
- Motor in holding torque state with PWM ≥ 99% for more than 4 seconds.
- During rotation, position deviation ≥ +30,000 or ≤ -30,000.
- In holding torque state, position deviation ≥ +41 or ≤ -41.
Recovery conditions (any one is sufficient):
- Re-power the motor.
- Toggle START from Low → High again.
- Input a RESET signal.
⚠️ After recovery, previously input pulse commands are discarded and must be re-sent.
✅ Core Advantages over Stepper Motors
- No step-out: Closed-loop brushless control eliminates the high-speed loss of synchronization and accumulated error problems of stepper motors.
- Instant start/stop and reversal: No step-out concerns.
- Lower power consumption: Inherent advantage of brushless motors.
- Smaller and lighter: Better volume and weight than steppers at the same torque.
- Integrated positioning + holding torque: Automatically brakes when stopped; no external brake mechanism required.
🏭 Typical Application Scenarios
High-speed printers, copiers, financial equipment, medical devices, peristaltic pumps, mixing equipment, automation equipment, infusion pumps, injection pumps, home appliances, presses, processing/inspection equipment, etc. It can replace brushed motors and stepper motors, solving issues such as electromagnetic noise, short lifespan, low energy efficiency, and excessive vibration/noise.
Note: Models currently in mass production include:
24H055L010, 24H055M020, 24H266L100, 24H266L110, 24H266M040, 24H266M050, 24H704L530, 24H704M250, 24H704L150, 42M704L150, 42M704L530