C.E. Niehoff & Co. C715, C716 Troubleshooting Guides

C. E. Niehoff & Co.

BRUSHLESS ALTERNATORS

700 Series Troubleshooting Guide

for C715 and C716 Alternators

Hazard Definitions

These terms are used to bring attention to presence of hazards
of various risk levels or to important information concerning
product life.

CAUTION

personal injury or property damage if ignored.

NOTICE

maintenance that are important but not related to
personal injury hazards.

Indicates presence of hazards
that will or can cause minor

Indicates special instructions
on installation, operation or

Table of Contents

Section 1: Wiring Diagram ...................................... 2

Section 2: Basic Troubleshooting ............................ 3

Section 3: Advanced Troubleshooting ................4 – 6

Battery Conditions

NOTICE

conditions may be observed during cold start voltage tests.

• Maintenance/low maintenance battery:
— Immediately after engine starts, system volts

are lower than regulator setpoint with medium
amps.

— 3-5 minutes into charge cycle, higher system

volts and reduced amps.

— 5-10 minutes into charge cycle, system volts

are at, or nearly at, regulator setpoint, and
amps are reduced to a minimum.

— Low maintenance battery has same charac-

teristics with slightly longer recharge times.

• Maintenance-free battery:
— Immediately after engine start, system volts are

lower than regulator setpoint with low amps.

— 15-30 minutes into charge cycle, still low volts

and low amps.

— 15-30 minutes into charge cycle, volts increase

several tenths. Amps increase gradually, then
quickly to medium to high amps.

— 20-35 minutes into charge cycle, volts increase

to setpoint and amps decrease.

• High-cycle maintenance-free battery:
— These batteries respond better than standard

maintenance-free. Charge acceptance of these
batteries may display characteristics similar to
maintenance batteries.

Until temperatures of electrical
system components stabilize, these

Charge Volt and Amp Values

The volt and amp levels are a function of the battery­state of charge. If batteries are in a state of discharge,
as after extended cranking time to start the engine,
the system volts, when measured after the engine is
started will be lower than the regulator set point and
the system amps will be high. This is a normal
condition for the charging system. The measured

values of system volts and amps will depend on the
level of battery discharge, in other words, the greater
the battery discharge level the lower the system volts
and higher the system amps will be. The volt and
amp readings will change and system volts reading
will increase up to regulator set point and the system
amps will decrease to low level (depending on other
loads) as the batteries recover and become fully
charged.

Low Amps:Low Amps:

•

Low Amps: A minimum or lowest charging system

Low Amps:Low Amps:

amp value required to maintain battery state of
charge, obtained when testing the charging system
with a fully charged battery and no other loads
applied. This value will vary with battery type.

Medium Amps:Medium Amps:

•

Medium Amps: A system amps value which can

Medium Amps:Medium Amps:

cause the battery temperature to rise above the
adequate charging temperature within 4-8 hours
of charge time. To prevent battery damage the
charge amps should be reduced when battery
temperature rises. Check battery manufacturer’s
recommendations for proper charge amps rates.

High Amps:High Amps:

•

High Amps: A system amps value which can cause

High Amps:High Amps:

the battery temperature to rise above adequate
charging temperature within 2-3 hours. To prevent
battery damage the charge amps should be
reduced when the battery temperature rises.
Check battery manufacturer’s recommendations
for proper charge amp rates.

Battery Voltage:Battery Voltage:

•

Battery Voltage: Steady-state voltage value as

Battery Voltage:Battery Voltage:

measured with battery in open circuit with no
battery load. This value relates to battery-state of
charge.

Charge Voltage:Charge Voltage:

•

Charge Voltage: A voltage value obtained when

Charge Voltage:Charge Voltage:

the charging system is operating. This value will
be higher than battery voltage and must never
exceed the regulator voltage set point.

B+ Voltage:B+ Voltage:

•

B+ Voltage: A voltage value obtained when mea-

B+ Voltage:B+ Voltage:

suring voltage at battery positive terminal or
alternator B+ terminal.

Surface Charge:Surface Charge:

•

Surface Charge: A higher than normal battery

Surface Charge:Surface Charge:

voltage occurring when the battery is removed
from a battery charger. The surface charge must
be removed to determine true battery voltage and
state of charge.

Significant Magnetism:Significant Magnetism:

•

Significant Magnetism: A change in the strength

Significant Magnetism:Significant Magnetism:

or intensity of a magnetic field present in the
alternator rotor shaft when the field coil is ener­gized. The magnetic field strength when the field
coil is energized should feel stronger than when
the field is not energized.

Voltage Droop or Sag: Voltage Droop or Sag:

•

Voltage Droop or Sag: A normal condition which

Voltage Droop or Sag: Voltage Droop or Sag:

occurs when the load demand on the alternator is
greater than rated alternator output at given rotor
shaft RPM.

TG0007A

Page 1

Section 1: Wiring Diagram

C. E. Niehoff & Co.

BRUSHLESS ALTERNATORS

CEN C715 and C716 Alternators
Description and Operation

C715C715

The

C715 alternator (14 V, 360 A) and

C715C715

tor (14 V, 400 A) are internally rectified. All windings
and current-transmitting components are non­moving, so there are no brushes or slip rings to wear
out. This unit is externally energized through either
an ignition switch or an energize switch (commonly
an oil pressure switch), which activates regulator.
Field coil is then energized. Regulator maintains
alternator output voltage at regulated setting as
vehicle electrical loads are switched on and off.
Alternator output current is self-limiting and will not
exceed rated capacity of alternator.

A2-128 regulator used with all units has R terminal
for optional AC voltage tap. A 15.5 V regulator set­point is available for battery isolator applications.

Electromagnetic interference (EMI) is suppressed with
internal filters to acceptable levels defined by the
Society of Automotive Engineers (SAE) specification
J1113/41. A2-128 regulator will not reduce EMI from
sources such as antennas, poor cable routing prac­tice, or other electronic devices that cause EMI. If EMI
continues, consult an electromagnetic compliance
(EMC) specialist to determine EMI source.

C716C716

C716 alterna-

C716C716

B+ Terminal

E Terminal

R Terminal

F+ Terminal

G

G

G

G

G

B Terminal

Figure 1  C715/C716 Alternator with A2-128 Regulator

Page 2

Figure 2  C715/C716 Wiring Diagram

TG0007A

C. E. Niehoff & Co.

BRUSHLESS ALTERNATORS

Section 2: Basic Troubleshooting

A. Tools and Equipment for Job

• Digital Multimeter (DMM)

• Ammeter (digital, inductive)

• CEN Regulator Bypass Adapter A10-129

• Jumper wire

• 12 V test light

B. Identification Record

Complete the following for proper troubleshooting:

Alternator model number ______________________

o

Regulator model number _______________________

o

Setpoints listed on regulator ___________________

o

C. Preliminary Check-out

Check condition of items in Table 1 and correct if
necessary.

TABLE 1  System Conditions

SYMPTOM

Low Voltage Output

High Voltage Output

No Voltage Output

Check: loose drive belt; low

battery state of charge.

Check: current load on

system is greater than
alternator can produce.

Check: defective wiring or

poor ground path; low
regulator setpoint.

Check: defective alternator

and/or regulator.
Check: wrong regulator.
Check: high regulator set-

point.
Check: defective regulator.
Check: alternator.
Check: broken drive belt.
Check: battery voltage at

alternator output terminal.
Check: defective alternator

and/or regulator.

ACTION

D. Basic Troubleshooting

Inspect charging system componentsInspect charging system components

1.

Inspect charging system components

Inspect charging system componentsInspect charging system components
for damagefor damage

for damage

for damagefor damage

Check connections at B– cable, B+ cable, and
regulator harness. Repair or replace any dam­aged component before troubleshooting.

Inspect vehicle battery connectionsInspect vehicle battery connections

2.

Inspect vehicle battery connections

Inspect vehicle battery connectionsInspect vehicle battery connections

Connections must be clean and tight.

Determine battery voltage and state of chargeDetermine battery voltage and state of charge

3.

Determine battery voltage and state of charge

Determine battery voltage and state of chargeDetermine battery voltage and state of charge

If batteries are discharged, recharge or replace
batteries as necessary. Electrical system cannot
be properly tested unless batteries are charged
95% or higher.

Determine if battery isolator is usedDetermine if battery isolator is used

4.

Determine if battery isolator is used

Determine if battery isolator is usedDetermine if battery isolator is used
charging circuitcharging circuit

charging circuit

charging circuitcharging circuit

Check vehicle wiring diagram. If so, you must
jumper out isolator before troubleshooting. See
Chart 1 on page 4 for details.

Connect meters to alternatorConnect meters to alternator

5.

Connect meters to alternator

Connect meters to alternatorConnect meters to alternator

Connect red lead of DMM to alternator B+
terminal and black lead to alternator B–
terminal. Clamp inductive ammeter on B+ cable.

Operate vehicleOperate vehicle

6.

Operate vehicle

Operate vehicleOperate vehicle

Observe charge voltage.

CAUTION

shut down system. Electrical system damage may occur if
charging system is allowed to operate at high voltage. Go to
Table 1 at left.

If voltage is at or below regulator setpoint, let
charging system operate for several minutes to
normalize operating temperature.

Observe charge volts and ampsObserve charge volts and amps

7.

Observe charge volts and amps

Observe charge volts and ampsObserve charge volts and amps

Charge voltage should increase and charge amps
should decrease. If charge voltage does not
increase within ten minutes, continue to next
step.

BatteryBattery

8.

Battery is considered fully charged if charge

BatteryBattery

voltage is at regulator setpoint and charge amps
remain at lowest value for 10 minutes.

If charging systemIf charging system

9.

If charging system is not performing properly,

If charging systemIf charging system

go to Chart 1, page 4.

If charge voltage is above

16.5 volts, immediately

inin

in

inin

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Page 3

Section 3: Advanced Troubleshooting

C. E. Niehoff & Co.

BRUSHLESS ALTERNATORS

START HERE

è

Is there a battery isolator in the system?

Yes

Chart 1 – System Circuit

G

Install temporary jumper between one battery terminal and
alternator terminal on isolator. Use minimum 12 AWG wire.

CAUTION

voltage will be abnormally high and damage other components.

Do not operate charging system more than two
minutes with jumper installed. Charging system

G

For “no voltage output” condition: • with

• with

enerener

ener

enerener
ignition switchignition switch

ignition switch, go to Chart 3, page 6.

ignition switchignition switch

No

G

gize switchgize switch

gize switch, go to Chart 2, page 5.

gize switchgize switch

Page 4

TG0007A

C. E. Niehoff & Co.

BRUSHLESS ALTERNATORS

Chart 2 – No Alternator Output –

Section 3: Advanced Troubleshooting

EnerEner

gize Switchgize Switch

Ener

gize Switch – Test Charging Circuit

EnerEner

gize Switchgize Switch

STATIC TEST  ENGINE OFF, BATTERY SWITCH ON, KEY ON

Test for battery voltage at B+ terminal on alter nator to gr ound, then at F+ ter minal on regula­tor to ground. Does battery voltage exist?

(CONTD)

Yes

G

Jumper B+ terminal on alternator to E ter minal
on regulator. Touch shaft with steel tool to detect
significant magnetism. Is shaft magnetized?

Yes

No

G

Go to energize switch on engine in E circuit.
Test for battery voltage going into energize switch
from battery. Does battery voltage exist?

Yes

No

G

Repair vehicle circuit to
energize switch. Continue test.

G

Make sure jumper wire from alternator B+
terminal to regulator E terminal is still attached.

Test for battery voltage at energize switch E
terminal connection. Does battery voltage exist
at energize switch?

Yes

G

No

G

No

G

Repair vehicle wiring as necessary. Continue test.

Unplug alternator -to-regulator har ness. Plug CEN
Regulator Bypass Adapter A10-129 into harness
plug. Make sure black lead does not touch
ground. Clip red lead to B+ terminal on alternator.

G

(If Adapter is not available, connect jumper wire
from socket B on harness to alter nator B+ ter mi­nal.) Does spark occur at alternator B+ ter minal?

Yes

No

G

Disconnect Adapter or jumper
wire. Alternator is defective.

G

Touch black lead to ground on alternator case.
(If Adapter is not available, connect jumper wire
from socket C on harness to ground.) Spark will
occur at ground. Touch steel tool to shaft to
detect significant magnetism. Is shaft magne­tized?

Yes

No

G

E circuit from regulator
to energize switch is
good. Energize switch is
defective.

Repair vehicle circuit
from E teminal on
regulator to energize
switch on engine.

GG

Vehicle charging circuit test is complete.
Remove jumper wire. Run engine and
re-test charging circuit for operation.

SOCKET CONNECTIONS

Figure 3  Alternator-to-Regulator Harness Plug

Socket A B
Socket B Field +
Socket C Field 
Socket D Phase (R)
Socket E B+

TG0007A

G

Disconnect Adapter or jumper
wire. Alternator is defective.

G

G

Disconnect Regulator Bypass Adapter or jumper
wire. Connect DMM red lead to socket E in alter­nator -to-regulator plug. Connect black lead to
socket A in same plug. Does battery voltage exist?

Yes

No

G

Alternator is defective.

G

Regulator is defective.

Page 5

Section 3: Advanced Troubleshooting

(CONTD)

C. E. Niehoff & Co.

BRUSHLESS ALTERNATORS

Chart 3 – No Alternator Output –

STATIC TEST  ENGINE OFF, BATTERY SWITCH ON, KEY ON

Test for battery voltage at B+ terminal on alter nator to gr ound, then at F+ ter minal on regula­tor to ground. Does battery voltage exist?

Yes

G

Jumper B+ terminal on alter nator to E ter minal
on regulator. Touch shaft with steel tool to detect
significant magnetism. Is shaft magnetized?

Yes

No

G

Disconnect jumper. Apply 12 V test light to
regulator E terminal and ground. Does light
glow brightly?

Yes

No

G

Repair wiring or
ignition switch.

G

Run vehicle. Does charge voltage exist?

Yes

No

GG

System
operating
normally.

Jumper B+ terminal on
alternator to regulator
E terminal. Does charge
voltage exist?

Yes

G

Repair wiring
or ignition
switch.

No

G

Contact CEN
Service
Department
for assistance.

Ignition SwitchIgnition Switch

Ignition Switch – Test Charging Circuit

Ignition SwitchIgnition Switch

No

G

G

G

Repair vehicle wiring as necessary. Continue test.

Unplug alternator -to-r egulator harness. Plug CEN
Regulator Bypass Adapter A10-129 into harness
plug. Make sure black lead does not touch
ground. Clip red lead to B+ terminal on alter nator.

G

(If Adapter is not available, connect jumper wire
from socket B on harness to alter nator B+ ter mi­nal.) Does spark occur at alternator B+ ter minal?

Yes

G

Disconnect Adapter or jumper
wire. Alternator is defective.

Touch black lead to ground on alternator case.
(If Adapter is not available, connect jumper wire
from socket C on harness to ground.) Spark will
occur at ground. Touch steel tool to shaft to
detect significant magnetism. Is shaft magne­tized?

Yes

Disconnect Adapter or jumper
wire. Alternator is defective.

G

Disconnect Regulator Bypass Adapter or jumper
wire. Connect DMM red lead to socket E in alter­nator-to-regulator plug. Connect black lead to
socket A in same plug. Does battery voltage exist?

Yes

No

G

No

G

No

SOCKET CONNECTIONS

Socket A B
Socket B Field +
Socket C Field 
Socket D Phase (R)
Socket E B+

Figure 4  Alternator-to-Regulator Harness Plug

Page 6

Alternator is defective.

G

G

Regulator is defective.

TG0007A

C. E. Niehoff & Co.

BRUSHLESS ALTERNATORS

Notes

TG0007A

Page 7

Notes

C. E. Niehoff & Co.

BRUSHLESS ALTERNATORS

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

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

Page 8

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

E-mail us at

[e-mail]

TG0007A