Datasheet

3 Fluke Corporation Fluke MDA-510 and MDA-550 Motor Drive Analyzer
Voltage modulation
Measurements of the Pulse Width Modulated signal are used to
check for high voltage peaks which can damage motor winding
insulation. The rise time or steepness of impulses is indicated by
the dV/dt reading (rate of voltage change over time), this should
be compared to the motor’s specified insulation. The measure-
ments can also be used to measure switching frequency to identify
whether there is a potential issue with electronic switching, or
with grounding, where the signal floats up and down.
Motor input
Ensuring that voltage is being supplied at the motor input termi-
nals is key, and the selection of cabling from drive to the motor
is critical. Incorrect cabling selection can result in both drive and
motor damage due to excessive reflected voltage peaks. Checking
that the current present at the terminals is within the motor rating
is important as over current condition could cause the motor to run
hot, decreasing the life of the stator insulation which can result in
the early failure of the motor.
Motor shaft voltage
Voltage pulses from a variable speed drive can couple from a
motor’s stator to its rotor, causing a voltage to appear on the rotor
shaft. When this rotor shaft voltage exceeds the insulating capac-
ity of the bearing grease, flashover currents (sparking) can occur,
causing pitting and fluting of the motor bearing race, damage that
can cause a motor to fail prematurely. The MDA-550 Series ana-
lyzers are supplied with carbon fiber brush probe tips that can
easily detect the presence of destructive flashover currents, while
the impulse amplitude and count of events will enable you to take
action before failure occurs. The addition of this accessory and
capability of the MDA-550 allows you to discover potential damage
without investing in expensive permanently installed solutions.
Step-by-step guided measurements ensure you have the
data you need, when you need it
The MDA-500 Series is designed to help you quickly and easily
test and troubleshoot typical problems on three-phase and
single-phase inverter type motor-drive systems. The on-screen
information, and step-by-step setup guidance make it easy to con-
figure the analyzer and get the drive measurements you need to
make better maintenance decisions, fast. From power input to the
installed motor, the MDA-500 provides the measurement capability
for the fastest motor-drive troubleshooting.
Voltage modulation with zoom
Motor shaft voltage discharge event counts