C.E. Niehoff & Co. C190 Troubleshooting Guides

C190 Series Alternator

Quick Troubleshooting Guide

Repair of this equipment shall only be carried out by C.E. Niehoff & Co.

This symbol is used to indicate presence

WARNING

of hazards that can cause severe personal
injury, death or substantial property damage.

The alternator contains no user serviceable

WARNING

parts. DO NOT DISMANTLE. Failure to follow
any instructions in the troubleshooting guide may
result in misdiagnosis of alternator function and
void the warranty.

DO NOT DISASSEMBLE. The cover O-ring may

WARNING

dislodge and cause failure of the fl ameproof
protection features. Verify that there is NOT a
gap between the cover and the alternator
housing.

Tools and Equipment for Testing

• Digital Multimeter (DMM)

• Ammeter (digital, inductive)

• Test bench with 5–10 hp motor able to drive alterna­tor to 8500 rpm. Mount alternator per test bench
manufacturer’s instructions. Make sure test bench
batteries are charged at 95% or higher.

On-Bench Tests to be Performed at
CEN Authorized Testing Facility

• Alternator rated output (listed on nameplate)
±10% is determined at 5000 rpm at 72ºF.

• Do not conduct test for longer than 20 minutes.

• Alternator/internal regulator should be connected
properly to test bench.

Alternator/internal regulator will
not test accurately without being
properly connected to power
source.

ON-BENCH TEST 1: NO-LOAD TEST
(Refer to Table 1)

With battery connected and no electrical load,
run alternator at 2000-2500 rpm shaft speed.

• If alternator passes No-Load Test, go to Full Load Test.

• If alternator fails No-Load Test, alternator should

be replaced.

NOTICE

TABLE 1 No- Load Test

ALT. AMPS VOLTS

C193 5-20 27.0-28. 2

C192 5-20 13.0-14. 2

ON-BENCH TEST 2: FULL LOAD TEST

On-Vehicle Troubleshooting on Site

If a no-charge condition is suspected, check that charge
light on vehicle comes on when master battery switch is
on:

• If light is not on, check/repair vehicle wiring to light.
Retest system.

• If light is on and no-charge condition is suspected,
measure battery voltage between B+ and B– from
the alternator harness where they connect to the
batteries.

— 28 V system: 27.0-28.2 V

— 14 V system: 13.0-14.2 V

If voltage reading is out of specs, remove alternator

with cable intact and take to CEN autorized service
dealer for further testing (refer to "On Bench Tests").

If no battery voltage is read at battery connections,

investigate vehicle side of circuit to determine cause.

If you have questions about your alternator or any of these inst ructions, or if you need to locate a Factory Authorized Service Dealer, please contact us at:

C. E. Niehoff & Co.• 2021 Lee Street • Eva nston, IL 60202 USA

TEL: [phone] USA and Canada • TEL: [phone] outside USA and Canada • FAX: [phone]

TG76A

E-mail us at [e-mail]

(Refer to Table 2)

With load set to rated output (listed on nameplate) ±
10%, run alternator at 5000-8500 rpm shaft speed.

• If alternator passes Full Load Test, alternator is
functioning properly.

• If alternator fails Full Load Test, alternator should
be replaced.

TABLE 2 Full Load Test

ALT. AMPS VOLTS

C193 30-35 27.0 -2 8.2

C192 60 -70 13.0-14.2

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