Danfoss VLT series Service Manual

5-7
VLT is a registered Danfoss trademark
5.1.3.2 Main Rectifier Circuit Test E-frames Part I
1. Connect positive (+) meter lead to positive (+)
DC bus connector MK105 (A) on power card.
2. Connect negative (–) meter lead to terminals L1,
L2, and L3 in turn. If a disconnect option is
used, measure on top side of fuses.
Each reading should show infinity. The meter will start at a low
value and slowly climb towards infinity due to capacitance within
the drive being charged by the meter.
Incorrect Reading
With the Part I test connection, the SCR modules are blocking
current flow. A short indicates a shorted SCR module.
5.1.3.3 Main Rectifier Circuit Test E-frames Part II
1. Reverse meter leads by connecting negative (–)
meter lead to positive (+) DC bus connector
MK105 (A) on power card.
2. Connect positive (+) meter lead to L1, L2, and
L3 in turn. Each reading should show open.
Incorrect Reading
With the Part II test connection, the SCR modules are blocking
current flow. A short indicates a shorted SCR module.
5.1.3.4 Main Rectifier Circuit Test E-frames Part III
1. Connect positive (+) meter lead to negative (-)
DC bus connector MK105 (B) on power card.
2. Connect negative (–) meter lead to terminals L1,
L2 and L3 in turn. Each reading should show a
diode drop.
Incorrect Reading
With the Part III test connection, the diodes in the main rectifier
diode modules are forward biased. The meter reads the diode
drops. If a short circuit or an open circuit exists, the diode
module is damaged.
5.1.3.5 Main Rectifier Circuit Test E-frames Part IV
1. Reverse meter leads by connecting negative (–)
meter lead to negative (-) DC bus connector
MK105 (B) on power card.
2. Connect positive (+) meter lead to L1, L2 and L3
in turn. Each reading should show infinity.
Each reading should show infinity. The meter will start at a low
value and slowly climb toward infinity due to capacitance within
the drive being charged by the meter.
Incorrect Reading
With the Part IV test connection, the diodes in the main diode
modules are reversed biased. If a short circuit exists, the diode
module is damaged.
Continue to Soft Charge Rectifier Tests: E-frames, 5.1.4.

Danfoss VLT series Specifications

General

Series	VLT
Category	DC Drives
Output Voltage	0-100% of input voltage
Protection Features	Overvoltage, Undervoltage, Overcurrent, Overtemperature, Short Circuit, Ground Fault
Communication Interfaces	Profibus, CANopen
Enclosure Rating	IP20, IP21, IP55, IP66
Cooling Method	Forced Air Cooling, Convection Cooling
Control Mode	Sensorless Vector, Closed Loop Vector
Ambient Temperature	-10°C to +50°C (14°F to 122°F)