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DONG-AH

DARF-D 22 RECTIFIER UNIT, MARINE HALF-WAVE RECTIFIER MODULE BY DONG-AH J.T. CO. LTD.

DARF-D 22 RECTIFIER UNIT, MARINE HALF-WAVE RECTIFIER MODULE BY DONG-AH J.T. CO. LTD.

$124.34 USD
$124.34 USD $124.34 USD
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Condition new
type half-wave rectifier module
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Description


DARF-D 22 RECTIFIER UNIT, MARINE HALF-WAVE RECTIFIER MODULE BY DONG-AH J.T. CO. LTD.

The new DARF-D 22 RECTIFIER UNIT from DONG-AH J.T. CO. LTD. provides efficient marine half-wave rectifier functionality for reliable power conversion.

The new DARF-D 22 RECTIFIER UNIT from DONG-AH J.T. CO. LTD. is a professional marine half-wave rectifier module designed for efficient power conversion in marine applications. Featuring high reliability and optimal performance, this module ensures smooth operation in demanding environments.

DARF-D 22 Marine Half-Wave Rectifier Unit by Dong-Ah J.T.

The Dong-Ah J.T. Co. Ltd. DARF-D 22 Rectifier Unit is a heavy-duty, marine-grade half-wave rectifier module explicitly engineered for shipboard hoists, gantry cranes, and industrial winches. Its primary function is to convert incoming Alternating Current (AC) from the vessel's or facility's power grid into Direct Current (DC), providing the necessary power to reliably actuate and release the electromagnetic holding brake on the motor.

Built to survive the unforgiving marine environment, the DARF-D 22 is fully encapsulated in premium resin, offering exceptional resistance to high-frequency vibrations, salt spray, and extreme humidity. This robust construction ensures that your critical lifting equipment operates safely, preventing catastrophic load slippage caused by brake power failures.

Detailed Technical Specifications

Parameter Specification Data
Manufacturer Dong-Ah J.T. Co., Ltd.
Model Number DARF-D 22
Rectification Type Half-Wave Rectifier (Output DC Voltage ≈ 0.45 × Input AC Voltage)
Typical Application Electromagnetic Brake Release for Marine Cranes & Hoists
Input / Output Specifications Please verify maximum Voltage (V) and Current (A) on original OEM nameplate before installation.
Housing Protection Potted/Encapsulated module (Shock, vibration, and moisture resistant)
Mounting Configuration Terminal box / Control panel mounting

Marine Application & Maintenance Value

In lifting applications, the motor brake is "fail-safe"—meaning strong springs clamp the brake shut when the power is off. The DARF-D 22 rectifier provides the DC power to the brake's electromagnetic coil, pulling against the springs to release the brake so the motor can turn.

  • Preventive Maintenance: Marine environments subject electrical components to severe thermal cycling. Replacing a degraded rectifier prevents "dirty" or weak DC output, which can cause the brake pads to drag, overheat, and destroy the hoist motor.
  • Diagnostic Clarity: Because it is a half-wave unit, technicians can easily diagnose its health by measuring the AC input and verifying the output is consistently ~45% of the input value as DC.

FAE Tool: Half-Wave Brake Rectifier Diagnostic Calculator

Is your crane failing to lift because the brake won't release? Use this tool to calculate the exact DC voltage you should be reading with your multimeter across the brake coil based on your measured AC input voltage. This applies to all standard half-wave rectifiers like the DARF-D 22.

*Measure this at the rectifier's AC input terminals (~).
*Input your field reading for instant health diagnosis.

Brake Rectifier Troubleshooting FAQ

1. Why does my marine hoist motor hum but refuse to lift?
This usually indicates that the motor is receiving power, but the mechanical brake is failing to release, causing the motor to fight a locked shaft. Immediately check the DARF-D 22 rectifier. If there is AC voltage entering the module but no DC voltage exiting to the brake coil, the rectifier has failed.

2. Can I replace this half-wave rectifier with a full-wave rectifier?
No. A half-wave rectifier converts AC voltage to roughly 45% DC (e.g., 220VAC to 99VDC). A full-wave rectifier converts it to roughly 90% DC (e.g., 220VAC to 198VDC). If you install a full-wave rectifier on a half-wave brake coil, you will deliver double the required voltage, which will cause the coil to overheat and burn out within minutes.

3. I installed a new rectifier, but it blew immediately when I tested the crane. Why?
Rectifiers rarely fail on their own; they are usually killed by a downstream fault. Before installing a new rectifier, you must disconnect the brake coil wires and measure the coil's resistance (Ohms) with a multimeter. If the coil is short-circuited (reading 0 Ohms), it will draw massive current and instantly destroy any new rectifier you install. You must replace the brake coil first.

About Koeed Automation

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At Koeed.com, we are professional architects of the industrial electronics supply chain. We specialize in providing high-performance PLCs, HMIs, Servo Motors, Drives, and Converters to ensure that modern manufacturing operations remain efficient, reliable, and future-proof in 2026’s competitive landscape.

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Supporting your vision for a smarter, more efficient industrial future.

Alternative Names


  • DARF-D 22
  • Dong-Ah Rectifier Unit

Special Reminder

Important

If you have any questions about product information and prices, please feel free to contact us by email or WhatsApp. We will respond quickly.

  • Business Days Only (Monday through Saturday)
  • It takes up to 10 days from the time of ordering (excluding Saturdays and Sundays) to the time of delivery to your designated location. Worldwide delivery.
  • Within 3 days after placing the order, we will send you photos and videos of the product via email or WhatsApp for confirmation

International shipping - items may be subject to customs processing depending on the item's customs value.
Sellers declare the item's customs value and must comply with customs declaration laws.
As the buyer, you should be aware of possible:

  • Delays from customs inspection.
  • Import duties and taxes which buyers must pay.
  • Brokerage fees payable at the point of delivery.

Shipping Policy

Global Delivery

We ship to customers all over the world. Our primary logistics providers are DHL, UPS, TNT, FedEx, and EMS.

Processing Time

All orders are processed within 72 hours of purchase. Please note that this applies to business days only.

Shipping Rates & Delivery Estimates

Shipping charges for your order will be calculated and displayed at checkout. Delivery estimates are within 7-14 days. Please note that these shipping times are only estimates and unfortunately, cannot be guaranteed.

Shipment Confirmation & Order Tracking

You will receive a Shipment Confirmation email once your order has shipped containing your tracking number(s). The tracking number will be active within 24 hours.

Customs, Duties, and Taxes

Please note, international shipping services do vary from country to country. To find out the exact services that are available, please put in your full address at checkout. Shipping internationally does mean that you may be required to pay customs and import taxes. All international customers are responsible for the customs rates within their own country. For further information, we recommend contacting your local customs office.

Damages

We take every reasonable precaution to ensure that products are not damaged. If the item is damaged in transit, please immediately contact us. We are not liable for any products damaged or lost during shipping. If you received your order damaged, please contact the shipment carrier to file a claim. Please save all packaging materials and damaged goods before filing a claim.

Force Majeure

When encountering with force majeure, the processing of orders will be delayed. Nevertheless, it is ensured that your order will be processed in a fast manner when weather permits.

Address Verification

Please verify you have the correct shipping address on your order PRIOR to making payment as this is the address we will ship to.

Return Policy

For more information, visit our Return Policy page.

International shipping - items may be subject to customs processing depending on the item's customs value.

Sellers declare the item's customs value and must comply with customs declaration laws.
As the buyer, you should be aware of possible:
• Delays from customs inspection.
• Import duties and taxes which buyers must pay.
• Brokerage fees payable at the point of delivery.

Contact Us

If you have any questions about your order, please contact us at moritta@koeed.com.

Return Policy

Return and Refund Policy

We want you to be completely satisfied with your purchase on our store. If for any reason you are not entirely satisfied, we're here to help!

Returns

You have a generous 30 calendar days to return an item from the date you received it. To be eligible for a return, ensure the item is in its original, unworn, and unused condition with tags and packaging intact. Retain your receipt or proof of purchase for eligibility. Please note that certain items are non-returnable like perishables, custom products, personal care goods, hazardous materials, flammable liquids, and gases. Reach out for clarifications on specific items.

Return Process

Commence the return process by reaching out to us at moritta@koeed.com. Upon approval, we will furnish you with a return shipping label and detailed instructions for dispatching your package. Unnotified returns will not be accepted.

Damages and Issues

Kindly review your order upon delivery. Notify us promptly if it arrives defective, damaged, or incorrect. We will address the matter swiftly.

Exchanges

Facilitate a swift exchange by returning the original item once approved and making a new purchase.

EU 14-Day Cooling Off Period

EU-bound shipments allow a 14-day cancellation or return period without justification. Conditions mirror standard returns.

Refunds

Upon receiving and inspecting your return, we’ll inform you of the refund status. Approved refunds are automatically processed within 10 business days via the initial payment method. Allow time for financial institutions to finalize the refund. For delays exceeding 15 business days post-approval, contact us at moritta@koeed.com.

Shipping

You will be responsible for paying for your own shipping costs for returning your item. Shipping costs are non-refundable. If you receive a refund, the cost of return shipping will be deducted from your refund.

Contact Us

If you have any questions on how to return your item to us, feel free to contact us at moritta@koeed.com.

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