Every Degree Counts
——How the JGB37-520 Encoder Gear-Motor Is Rewriting the Rules for PV Tracking
——How the JGB37-520 Encoder Gear-Motor Is Rewriting the Rules for PV Tracking
By Smart PV Editorial Team
July 14, 2025
July 14, 2025
-
The Challenge
In March 2024, a 50 MW agrivoltaic plant in Ningxia, China, was bleeding energy:
• Legacy DC linear actuators had no feedback; strong winds knocked panels out of alignment, cutting daily yield by 2.1 %.
• Technicians climbed the racks twice a month to re-calibrate—CNY 150 k a year in OPEX.
The owner issued a brief: “retrofit must be low-cost, reliable, and remotely closed-loop.”
They chose the CNY 89 JGB37-520 encoder gear-motor to drive the elevation axis—and upgraded 1,920 trackers in six weeks. -
Technical Fit
Motor spec
• JGB37-520-12V-90: 12 V, 90:1 all-metal planetary, 6.5 N·m rated torque
• Magnetic AB encoder: 11 PPR → 3,960 counts/° after gearbox—fine enough to spot a 0.02° error
System stack
• 1 motor + 1 STM32G0 MCU + 4G Cat.1 modem per tracker
• 50 ms local closed loop; cloud SCADA pushes solar angles; offline ephemeris if the link drops
• 1 motor + 1 STM32G0 MCU + 4G Cat.1 modem per tracker
• 50 ms local closed loop; cloud SCADA pushes solar angles; offline ephemeris if the link drops
-
Retrofit Recipe
-
Mechanical drop-in
Remove actuator, bolt motor’s 8 mm D-cut shaft to existing worm gear—15 min per tracker. -
Control algorithm
• Dual PID: inner speed, outer position; wind-gust feed-forward.
• Storm mode: if encoder sees >0.2°/s rotation at ≥8-level wind, panels flatten automatically. -
Connectivity
• Sync ephemeris once a day (<3 MB monthly).
• OTA firmware for PID tuning and backlash tables.
-
Field Results
| Metric | Before | After | Gain |
|---|---|---|---|
| Tracking accuracy | ±3° | ±0.15° | 95 % |
| Wind-induced faults | 12/year | 0 | — |
| Energy uplift | baseline | +4.8 % | +2.1 GWh/year |
| Maintenance labor | CNY 150 k/year | CNY 20 k/year | 87 % saved | -
Snapshot
July 15, 2024, 14:30. Gusts hit 25 m/s. Legacy trackers rattled out of position; 960 retrofitted units lay flat in six seconds. Cloud logs: max angular speed 0.18°/s—no alarms fired. The owner laughed, “The motors know when to take a nap.” -
Business Impact
• 8,000 motors delivered, installed, and commissioned in 3 months—99.7 % batch yield.
• Total retrofit budget: CNY 1.8 M; payback expected in 10 months.
• Solution now replicated in two 200 MW plants in Qinghai and Inner Mongolia—8,000 additional trackers online. -
Key Takeaways
-
Planetary + magnetic encoder turns an “economy” motor into a precision solar tracker.
-
90:1 is the sweet spot: enough torque, high back-drive resistance, no brake needed.
-
For mass field retrofits, keep three things unchanged: mounting holes, cable harness, control box. The JGB37-520’s 37 mm OD and circular flange match legacy actuators perfectly.
Epilogue
From farmland to the cloud, an CNY 89 JGB37-520 encoder gear-motor closes the loop on every degree—delivering low-cost, high-precision, maintenance-free tracking. Its next stop might be 100,000 smart bike locks or automated greenhouse louvers. The age of affordable closed-loop motion has arrived.
From farmland to the cloud, an CNY 89 JGB37-520 encoder gear-motor closes the loop on every degree—delivering low-cost, high-precision, maintenance-free tracking. Its next stop might be 100,000 smart bike locks or automated greenhouse louvers. The age of affordable closed-loop motion has arrived.