21489731 Voltage Regulator | Genuine Volvo Penta Part

🔧 Product Description

An electronic regulator used in the assigned Volvo Penta alternator or charging system to maintain controlled battery-charging voltage.

🚤 Compatibility

Typically suits:

• Volvo Penta TD420VE
• Volvo Penta TAD620VE
• Volvo Penta TAD420VE

• Engine Family: TD, TAD

⚙️ Key Features

• Regulates alternator field current
• Protects batteries and electrical equipment
• Engine-duty electronic construction
• Correct alternator interface
• Application and voltage must match the original unit

🔌 Function

The regulator adjusts alternator output so system voltage remains within the required range as engine speed and electrical load change.

⚠️ Common Signs of Failure

• Low or excessive charging voltage
• Battery warning alarm
• Batteries overcharging or remaining discharged
• Intermittent alternator output
• Burnt or corroded terminals
• Voltage unstable with changing engine speed

🛠️ Service Notes

• Isolate the batteries at the main switch and disconnect the negative lead before working on the charging circuit, and never disconnect a battery while the engine is running
• Rule out the simple causes before condemning a regulator — a slack or glazed drive belt, corroded or loose battery and alternator connections, a poor engine-to-battery earth, or a tired battery all produce the same symptoms
• Check the brushes and slip rings while the regulator is off; a worn brush set gives the same low or erratic output
• Fit clean and dry, seat any insulating washers and bushes in their original order so nothing bridges across them, and tighten the terminals firmly without crushing them
• Measure charging voltage at the battery with the engine running once the regulator is fitted, and compare it with the value specified for your engine and battery type

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 21489731 → Supersedes 21301527 → Supersedes 20509482

OEM / Related Numbers

• 21301527 earlier number superseded by this part
• 20509482 earlier number superseded by this part
• 21489722 - Related alternator reference

📦 Condition

• Genuine Volvo Penta part
• Brand new
• Supplied in original or equivalent packaging