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Special Test Equipment
10 Special Test Equipment
10.1 Test Equipment
Test tools have been developed to aid in troubleshooting
these products. It is highly recommended for repair and
servicing this equipment that these tools be available to
the technician. Without them, some troubleshooting
procedures described in this manual cannot be carried out.
Although some test points can be found inside the
frequency converter to probe for similar signals, the test
tools provide a safe and sure location for making necessary
measurements. Test equipment described in this section is
available from Danfoss.
WARNING
Using the test cable allows powering the frequency
converter without having to charge DC bus capacitors.
Main input power is required and all devices and power
supplies connected to mains are energised at rated
voltage. Use extreme caution when conducting tests on a
powered frequency converter. Contact with powered
components could result in electrical shock and personal
injury.
10.1.1 Split-bus Power Supply
Powering the drive in the split bus mode allows dynamic
testing on the drive in a safer manner.
In the split bus mode, the DC bus in each module is split
into two portions. One connects to the DC bus and power
card to provide low voltage power for the SMPS. By
powering only the SMPS in each module, the various logic
circuits can be tested without the danger of damaging the
power components.
The other provides low voltage power to the DC capacitors
and the output IGBTs for test purposes. A low voltage
power supply connected to the DC bus allows testing the
functionality of the output section safely.
The following procedure will be referred to throughout the
dynamic test section.
Powering the Drive in Split Bus Mode
1.
Ensure that AC power has been removed and
that all DC capacitors are fully discharged.
2.
Remove the top and bottom safety covers from
each inverter module as well as the top safety
cover from the rectifier module.
3.
If a motor is connected to the drive, remove all
output bus bars from each inverter module. Also
remove the brake bus bars if the drive is
equipped with the brake option.
High Power Service Manual for Modular F Frame Drives
10.1.2 Signal Test Board (p/n 176F8437)
The signal test board provides access to a variety of signals
that can be helpful in troubleshooting the frequency
converter.
The signal test board is plugged into the 30 pin panel
connector on the top of each inverter module. Points on
the signal test board can be monitored with or without
the DC bus disabled. In some cases, the frequency
converter will need the DC bus enabled and operating a
load to verify some test signals.
The following is a description of the signals available on
the signal test board. The section Test Procedures describes
when these tests would be called for and what the signal
should be at that given test point.
Illustration 10.1 Signal Test Board
®
MG90K202 - VLT
is a registered Danfoss trademark
4.
Remove the plugs from the 6-pin sockets on each
module.
5.
Connect the power supply cable (p/n 176F8766)
to the 6-pin sockets of each module.
6.
Connect a 610 – 800VDC power supply to the
input end of the power supply cable.
7.
Apply power to the power supply. The LCP
should light up as if the drive were powered
normally.
8.
Warning 24, External Fan Failure will be displayed
in the LCP. This is because the fan circuitry is not
powered in this mode. This will not affect the
operation.
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