APPLICATION
Applications where a voltage regulator is powered by a permanent magnet generator (PMG), auxiliary winding, or
generator output (shunt fed) usually do not require the protection of an ICRM. These sources usually have a
higher source impedance which inherently minimizes inrush current. Also, these sources are typically connected
directly to the voltage regulator with no interposing relays, contactors, or switches. If this is the case, then no
inrush occurs since the source voltage ramps up to its rated value.
However, if rated or near rated voltage is applied to the voltage regulator, then some amount of inrush current is
expected and an ICRM should be considered. Typically, voltage regulators in these applications receive power
from a station service bus that is switched by a relay or contactor. Applications where a PWM type voltage
regulator is powered by a low-impedance source need an ICRM to minimize the amount of inrush current.
To summarize, if the voltage that powers the voltage regulator ramps up to nominal as the generator comes up to
rated speed, then an ICRM is not needed. If this is not the case, an ICRM should be used. If you are unsure
whether your application requires an ICRM, contact Basler Electric Technical Sales Support for assistance.
ICRM Versions
Two versions of the ICRM are available. Each version is uniquely suited to protect a specific family of Basler
Electric products. Table 1 lists each ICRM model, its part number, and the compatible products.
