Power supply ICOS-PS 3160 series
Installation, use and maintenance manual - EN
Ver. 1.05
30
This function is sometimes necessary when you supply power to servodrives, which may create a flow of elec-
tric power directed versus the power supply unit during the motor braking phase. This often happens during
cycles (cams) or during an emergency stop. During the braking, the energy coming from the load is stored in
the bus capacitors, which increase their voltage. If a braking circuit is not available the voltage might increase
uncontrollably, thus potentially damaging the devices, unless the servodrive (as usually happens) is disabled
due to overvoltage. Such mode of operation causes a disappearance of the braking torque, not acceptable in
most situations.
CAUTION
ATTENTION
To overcome this problem, it is necessary to dissipate the excess electric power, and this is obtained by
inserting a braking resistor. It is energized by the power supply unit only in case of real need, and it avoids
that the bus voltage reaches dangerous levels for the downstream devices and for the power supply unit itself.
The braking resistor must be adequately sized according to the following factors:
• operating voltage (during the braking phase, it can reach 450V DC);
• average power: it must be higher than the average power generated during the braking phase;
• peak power: it must be higher than the peak power generated during the braking phase;
• cooling system: natural or forced ventilation, liquid cooling, etc...
Large capacitors inside the device. Risk of Electric Shock; wait at least No. 600 seconds (10
minutes) after disconnecting power. Do not connect or disconnect cable and connectors be-
fore that time.
Hautes capacités présentes à l'intérieur de l'appareil. Risque de choc électrique; attendez
au moins 600 secondes (10 minutes) après la mise hors tension. Les câbles et les connec-
teurs ne doivent pas être connectés ou déconnectés avant la fin du temps indiqué.
