Power Module Electrical Evaluation - JLG 1930ES Service Maintenance Manual

Power Module Electrical Evaluation

Several basic electrical tests can be performed on the
Power Module. Failure of one of these evaluations is sig-
nificant and may indicate that the device is physically
damaged. If a Power Module is suspected to be faulty,
thoroughly examine the rest of the system for possible
damage.
Refer to Figure 7-2., Resistance Measurement. Disconnect
the Main Battery Disconnect and all cables from the Power
Module during this analysis. Wait 60 seconds after power
is disconnected to allow internal charge to dissipate (risk
of hazard, improper readings otherwise).
• Resistance >100kOhms all Terminals to Housing.
Ensure that there is an open-circuit between all termi-
nals of the Power Module and the module's aluminum
housing. The device is fully potted and all electronics
are insulted from the housing. Place the Black meter
lead on the housing and use the Red meter lead to
probe all terminals.
• Resistance < 2 Ohms between +B and M1. Ensure
that there is a short-circuit between the +B and M1 Ter-
minals. Internally, there is a low-impedance current
measurement shunt for the Armature portion of Trac-
tion. Place the Red meter lead on +B, and the Black
meter lead on M1.
• Resistance >1 MegaOhms between F1 and -B; F2
and -B. Ensure that there is an open-circuit between
the two Field Terminals (F1 & F2) and -B. Internally,
there are MOSFET transistors between these terminals
that should be high-impedance when the module is
un-powered. Place the Black meter lead on -B and the
Red meter lead on F1 / F1.
• Resistance >1 MegaOhms between F1 and +B; F2
and +B. Ensure that there is an open-circuit between
the two Field Terminals (F1 & F2) and +B. Internally,
there are MOSFET transistors between these terminals
that should be high-impedance when the module is
un-powered. Place the Black meter lead on +B and the
Red meter lead on F1 / F1.
3121166
SECTION 3 - CHASSIS & SCISSOR ARMS
• Resistance >100kOhms between P and -B. Ensure
that there is an open-circuit between the P and the -B
Terminals. Internally, there are MOSFET transistors
between these terminals that should be high-imped-
ance when the module is un-powered. Place the Black
meter lead on -B, and the Red meter lead on P . Note
that a measurement of increasing resistance (capacitor
charge) is normal, but a persistently low impedance is
not.
• Resistance >1kOhms between M2 and -B. Ensure
that there is an open-circuit between the M2 and -B
Terminals. Internally, there are MOSFET transistors
between these terminals that should be high-imped-
ance when the module is un-powered. Place the Black
meter lead on -B, and the Red meter lead on M2. Note
that a measurement of increasing resistance (capacitor
charge) is normal, but a persistently low impedance is
not.
• Resistance 120 Ohms between Pins 10 & 11.
Ensure that the resistor that terminates the CANbus is
within tolerance between pins 10 and 11 on the 12
position Mini-Fit Jr (Connector "B"). Place the Red
meter lead on pin 10, and the Black meter lead on pin
11. The resistance should measure between 110 - 130
Ohms.
– JLG Lift – 3-39