Perkins — Alternator - Test
Testing & diagnosis · Charging system
From a Perkins service manual covering: 402D-05, 403D-07, 403D-11, 403D-15, 404D-22, 404D-22T, 404D-22TA. Check it applies to your exact model before use.
Applies to: Perkins 402D-05, Perkins 403D-07, Perkins 403D-11, Perkins 403D-15, Perkins 404D-22, Perkins 404D-22T, Perkins 404D-22TA
Before you start
- Never disconnect any charging unit circuit or battery circuit cable from the battery when the charging unit is operated.
Procedure
- Put the multimeter positive lead on the Bat terminal; negative lead on ground or frame.
- Put an ammeter around the positive output wire of the alternator.
- Turn off all electrical accessories; turn off the fuel to the engine.
- Operate the starter motor for 30 seconds; wait two minutes to cool the starter motor.
- Start the engine and run at high idle.
- Check output current; initial charging current should equal or exceed minimum full load current.
- After approximately ten minutes, output voltage should be 14.0 ± 0.5 volts.
- After ten minutes the charging current should decrease to approximately 10 amperes.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Alternator output 14.0 ± 0.5 volts
- Charging current decreases to approximately 10 amperes
Full service-parts list: Perkins 402D-05 →, Perkins 403D-07 →, Perkins 403D-11 →, Perkins 403D-15 →, Perkins 404D-22 →, Perkins 404D-22T →, Perkins 404D-22TA →
Source: Perkins service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.