Alternator Regulators - PRESTOLITE Transistorized Regulator Model VSC: Testing

NOTE: Make certain alternator is operating properly before testing voltage regulator. See "Prestolite Alternator" in this section.

Connect ammeter and 1/4 ohm fixed resistor in series in charging line at alternator output terminal, connect voltmeter between alternator output terminal and ground at battery negative post.
Operate engine at 2000 RPM for approximately 15 minutes to stabilize temperature. Alternator output should be 10 amperes.
Check ambient temperature of regulator with accurate thermometer placed I" away from regulator case.
Alternator regulated voltage at indicated ambient temperature, should be within limits specified in specifications.

If voltage not within limits, replace regulator and repeat test. Regulator is sealed and is not adjustable.

Regulator Voltage Specifications (At Ambient Temperature)

⁽¹⁾Output Voltage

Ambient Temp. (°F)

Minimum

Maximum

0°

14.6

15.4

20°

14.6

15.3

40°

14.3

15.0

60°

14.1

14.9

80°

14.0

14.8

100°

13.8

14.6

120°

13.7

14.5

140°

13.6

14.4

160°

13.3

14.1

⁽¹⁾	With 10 ampere load