L21720A00 Power Supply Unit

Original OTC DAIHEN L21720A00 Robot Controller Power Supply Unit (JH01G)

OTC DAIHEN L21720A00 (Nameplate Identifier: L21720 / JH01G) serves as the critical electrical heart inside industrial robot control cabinets. As a genuine OEM power supply unit designed for demanding automated environments, it converts high-voltage workshop AC power into ultra-pure, noise-free, multi-channel isolated DC voltages required by the motherboard, servo amplifiers, and external I/O interfaces. Broadly compatible across OTC DAIHEN industrial robot series and select NACHI (Nachi-Fujikoshi) robot controllers, this core module is essential for ensuring 24/7 continuous operation while eliminating controller system halts and encoder step loss.

🌟 Core Advantages & Genuine OEM Reliability

• Ultra-Pure Multi-Channel Isolated DC Output: The 32-bit CPU and servo amplifiers inside robot controllers are extremely sensitive to voltage ripple. The L21720A00 stably delivers simultaneous isolated DC outputs including +5V (core logic board), ±15V (analog signal detection), and +24V (external I/O communication and mechanical brakes). The minimal ripple factor of genuine OEM power supplies prevents trajectory deviation and encoder communication faults.
• Industrial Short-Circuit & Overload Defense: Workshop power grids experience severe electrical noise and voltage surges during welding arc ignition. This unit incorporates industrial-grade overvoltage, overcurrent, and short-circuit active protection ICs alongside an integrated forced-cooling fan. In the event of an external short circuit, it instantaneously shuts down output, sacrificing itself to protect expensive controller motherboards and servo modules.
• Physical Poka-Yoke Error-Proof Connectors: Designed for rapid field maintenance, every output wiring socket on the L21720A00 features unique physical Poka-Yoke keying and orientation dimensions. Maintenance technicians can replace units rapidly without complex multimeter continuity mapping, achieving fool-proof, seconds-level production recovery.
• Reject Refurbished Hazards: Aftermarket refurbished power boards often contain aging capacitors that act like ticking time bombs, risking cascading short circuits that destroy motherboards. Our L21720A00 units are 100% brand-new, genuine Japanese imports, exponentially extending service life and eliminating hidden downtime costs.

📋 Technical Specifications & Configuration Matrix

⚠️ Purchasing Note: Please verify the metal nameplate on your faulty module before ordering to ensure the part identifier contains L21720 or JH01G.

Specification Parameter & Category	OEM Factory Rating & Description
Official Order Part Number / Identifier	L21720A00 / MODEL: L21720 (JH01G)
Compatible Industrial Robot Brands	OTC DAIHEN / Fully compatible with NACHI robots
Allowable Input Voltage Range	AC 200V~230V or AC 380V~480V (Verify cabinet configuration)
Core DC Output Specifications	+5V / ±15V / +24V and servo bus voltage
Protection & Thermal Mechanism	Automatic short-circuit/overvoltage/overcurrent defense & forced cooling fan
Safety Quality Standards	CE / UL certified for industrial control equipment
Standard Package Contents	New L21720A00 Power Supply Unit × 1 OEM mounting screw kit × 1 / Terminal identification sticker × 1

🔧 Power Supply Troubleshooting & Burn-Out Prevention Guide

• Mandatory Power-Off Discharge Protocol: The L21720A00 houses massive rectifier bridges and high-voltage filter capacitor arrays. Never reach inside or unplug connectors immediately after disconnecting the main cabinet power switch! Allow at least 5 to 10 minutes for the red residual charge LED on the power unit panel to extinguish completely, or verify zero residual DC voltage with a multimeter before touching terminals to prevent fatal electric shocks.
• Investigate External Short Circuits Before Power-Up: If your legacy power unit suffered electrical burn-out (e.g., burnt smell, blackened PCB, or blown fuses), strictly inspect external cabinet circuits with a megohmmeter and multimeter before installing and powering up the new L21720A00! Verify that external 24V I/O control harnesses (safety gates, E-stop loops) do not have short circuits to ground, and check servo motor power cables for insulation breakdown. Installing a new power unit without resolving the underlying short circuit will immediately destroy the replacement module upon power-up.
• Forced Cooling Fan Dust Maintenance: Power unit lifespan depends 80% on thermal dissipation efficiency. In welding workshops filled with conductive iron dust and fumes, the built-in cooling fan blades and intake grilles can quickly become clogged with sticky grime. Maintenance teams should open side cabinet doors quarterly and clean power supply surfaces carefully with dry compressed air to ensure smooth airflow across internal cooling fins.