Test Procedures VLT® HVAC Basic Drive Service Manual
/library/Danfoss/Ïðåîáðàçîâàòåëè ÷àñòîòû/VLT HVAC_Basic FC101/MG90X202-FC101 Service.pdf\nTest Procedures VLT® HVAC Basic Drive Service Manual
2 Introduction • Digital voltmeter/ohmmeter capable of reading
real RMS
WARNING • Analog voltmeter
DISCHARGE TIME! • Oscilloscope
Frequency converters contain DC-link capacitors that can
remain charged even when the frequency converter is not
• Current meter
powered. To avoid electrical hazards, disconnect AC mains,
any permanent magnet type motors, and any remote DC-.3 Static Test Procedures
link power supplies, including battery backups, UPS and
DC-link connections to other frequency converters. Wait for All tests should be made with a meter capable of testing
the capacitors to fully discharge before performing any diodes. Use a digital volt/ohmmeter (VOM) set on the
service or repair work. The amount of wait time is listed in diode scale or an analog ohmmeter set on Rx scale.
the Table 1.1. Failure to wait the specified time after power Before making any checks, disconnect all input, motor, and
has been removed before doing service or repair could brake resistor connections.
result in death or serious injury.
Static tests are performed without applying power to the
This section contains detailed procedures for testing frequency converter.
frequency converters. Previous sections of this manual
provide symptoms, alarms, and other conditions which
require additional test procedures to diagnose the
WARNING
Whenever power is applied to the frequency converter,
frequency converter further. The results of these tests
never disconnect the input cable. Disconnecting the input
indicate the appropriate repair actions. Again, because the
cable could result in electrical shock, personal injury, and
frequency converter monitors input and output signals,
death.
motor conditions, AC, and DC power and other functions,
the source of fault conditions may exist outside of the
frequency converter. Testing described here isolates many The purpose of performing static test is to check for any
of these conditions as well. Disassembly and Assembly possibility of short circuit of the power components.
Instructions (H or I-frame sizes frequency converters,
respectively), describes detailed procedures for removing.3.1 Pre-requisite
and replacing frequency converter components.
• Prepare the work area according to the ESD
Frequency converter testing is divided into Static Tests, and regulations. Ground ESD mat and wrist strap.
Dynamic Tests. Static tests are conducted without power Ensure that the ground connection between
applied to the frequency converter. Most frequency body, the ESD mat and the frequency converter is
converter problems can be diagnosed simply with these always present while servicing the drive. Handle
tests. Static tests are performed with little or no disassembled electronic parts carefully and always
disassembly. The purpose of static testing is to check for ESD protected.
shorted power components. Perform these tests on any
• Perform the static test before powering up the
unit suspected of containing faulty power components fault unit.
before applying power.
• Perform static test after completing the repair
and assembly of the frequency converter.
CAUTION • Connect the frequency converter to the mains
For dynamic test procedures, main input power is required. only after completion of static tests.
All devices and power supplies connected to mains are
energized at rated voltage. Use extreme caution when • All necessary precautions for system startup must
be completed before applying power to
conducting tests on a powered frequency converter.
frequency converter.
Contact with powered components could result in
electrical shock and personal injury.
Dynamic tests are performed with power applied to the
frequency converter. Dynamic testing traces signal circuitry
to isolate faulty components.
MG90X - VLT® is a registered Danfoss trademark
