User Manual
AMETEK Programmable Power
BPS Series
135
PFC failure denotes one or all three of the IGBT power modules on the large PFC heat sink have shorted,
and damaged the devices. This type of failure is sometimes accompanied by a popping sound as the large
PFC power devices give out. To diagnose this failure mode, the amplifiers must be removed and the cover
removed for inspection.
If there is any sign of damage, the PFC power devices must be replaced. If not, they need to be checked
for continuity using a DMM or diode checker.
In case of a PFC failure, older generation PFC control boards (7003-705 or 7003-712) may have sustained
damaged in the isolated gate drive section of the board and the board itself may have to be replaced. BPS
Systems with later generation 7003-716 PFC control boards generally will only require replacement of the
2A gate fuses to restore functionality.
If the PFC section looks intact, one of the output amplifier switches may have shorted.
The usual scenario is one or two of the IGBT switch devices on one of the 4 heat sinks get shorted.
Usually if the B+ device is failed, the B- device will also short. When these devices short, one or more of
the 30A fuses (F1 through F8) on the DC power distribution board will be open.
An amplifier device failure is not audible at all so there may be no indication of this other than checking as
follows:
1.
Measure the output voltage with Zero AC volts programmed.
2.
Remove any EUT from the output connections.
3.
Turn output ON and measure the AC and DC output. It should be close to zero.
4.
If the output reads –225VDC on the low range and close to 0 Vdc on the high range, then it is almost
certain that the fuse is blown and 1 or 2 IGBT devices are shorted.
Note that the measurement screen will not report the DC faulty output voltage in the AC mode, as the
measurements in this mode are AC coupled. Therefore, it is necessary to measure at the output terminals
with a DMM to determine the actual output. Alternatively, the BPS can be switched to AC+DC mode in
which case the internal measurements can be used instead.
If it is determined that it is an amplifier failure, the affected power MOSFET’s need to be replaced. If no
local service support is available, the amplifier may be exchanged completely. Contact customer service
for module exchange information.
8.5
Factory Assistance
If the problem with the cabinet or one of the power modules cannot be isolated, contact the factory for
assistance.
