Danfoss VLT FC Series, Руководство по обслуживанию

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8.2.3 Metering Tools
For best troubleshooting results, perform the static test
procedures described in this section in the order
presented.
Perform all tests with a meter capable of testing diodes.
Use a digital Volt-Ohm Meter (VOM) set on the diode scale
or an analog ohmmeter set on Rx100 scale. Before making
any checks, disconnect all input, motor, and brake resistor
connections.
Diode drop
A diode drop reading varies depending on the model of
ohmmeter. Whatever the ohmmeter shows as a typical
forward bias diode is defined as a diode drop in these
procedures. With a typical DVM, the voltage drop across
most components is around 0.300 to 0.500. The opposite
reading is referred to as infinity, and most show the value
OL for overload.
8.3 Test Preparations
NOTICE
TEST ORDER
For best results, perform the static test procedures in this
section in the order they appear.
Observe the following safety precautions before
performing the static tests:
•
Prepare the work area according to the ESD
regulations.
•
Ground the ESD mat and wrist strap.
•
Ensure that the ground connection between
body, the ESD mat, and the drive is always
present while performing service.
•
Handle disassembled electronic parts with care.
•
Perform the static tests before powering up the
faulty unit.
•
Perform the static tests after completing the
repair and assembly of the drive.
•
Connect the drive to the mains only after
completion of static tests.
•
Complete all necessary precautions for system
start-up, before applying power to the drive.
WARNING
DISCHARGE TIME
The drive contains DC-link capacitors, which can remain
charged even when the drive is not powered. High
voltage can be present even when the warning LED
indicator lights are off. Failure to wait the specified time
after power has been removed before performing service
or repair work can result in death or serious injury.
•
Stop the motor.
•
Disconnect AC mains and remote DC-link power
supplies, including battery back-ups, UPS, and
DC-link connections to other drives.
•
Disconnect or lock the motor.
•
Disconnect any brake option.
•
Disconnect any regen/load share option.
•
Wait for the capacitors to discharge fully. The
minimum waiting time is specified in the
following discharge time table and is also
visible on the drive label.
•
Before performing any service or repair work,
use an appropriate voltage measuring device to
make sure that the capacitors are fully
discharged. For parallel drive modules, measure
DC-bus capacitor voltages before and after the
individual DC fuses.
Enclosure Size Minimum waiting time
D1h–D8h drives 20 minutes
J8–J9 drives 20 minutes
D9h–D10h enclosed drive systems 20 minutes
Da2/Da4/Db2/Db4 parallel drive systems 20 minutes
E1h–E4h drives
40 minutes
E5h–E6h enclosed drive systems 40 minutes
Table 8.4 Discharge Time
Test Procedures Service Guide
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