Power supply ICOS-PS 3160 series
Installation, use and maintenance manual - EN
Ver. 1.05
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In order to avoid this problem, the dynamic braking stage dissipates this energy in a power resistor (external
to the power supply unit and properly sized). It is connected to the bus voltage using an IGBT transistor, which
is activated only when the bus exceeds a preset threshold. It is disabled when the bus voltage decreases
below the threshold, thus avoiding unnecessary dissipation of power.
Depending on the resistor value and on the braking power, the bus voltage might anyway increase up to
dangerous levels; in this case, the power supply unit is protected by downstream devices: the ICOS 320X
servodrivers are suited for this purpose.
The activation of the dynamic brake output is signalled by the BRK LED. Paragraph 6.4 describes the anoma-
lies that might affect the dynamic braking system.
6.6 Missing phase
Feeding the equipment with a three-phase power line, it might occur that a phase is missing (for example, due
to the interruption of a protection fuse). In this case, the RMS input current on the remaining phases would in-
crease considerably and might damage the power supply unit.
In order to avoid this problem, a dedicated circuit immediately detects if a phase is missing. This control is ac-
tive only in case the power supply unit is set for three-phase operation. If the phase absence is longer than 5
seconds, the power supply unit enters the alarm status.
See paragraphs 6.3 and 6.4 for the signal modes.
6.7 Automatic capacity discharge operation (ICOS-PS 3162 only)
In some cases it is useful that when the main power supply is interrupted, for example when this is disconnect-
ed by safety switches, the energy still present inside the power supply is quickly eliminated in order to prevent
the devices connected downstream from it. they can use to make unwanted movements.
This can be done by burning this energy on a resistor specifically connected to the dynamic brake output or on
the same resistor used for dynamic braking.
The automatic discharge is activated 100ms from the disconnection of the main power supply; should the pow-
er supply voltage return during the discharge phase, the latter would be immediately interrupted, returning the
power supply to its normal operating state.
The discharge time varies according to the DC Bus voltage present inside the power supply and the discharge/
braking resistor value connected to the dynamic brake output.
