maxon motor
14
maxon EC motor
EC 20 flat with integrated electronics
Operating Instructions
September 2010 Edition / document number 903155_PDF_E - 07 / subject to change
6 Protective functions
6.1 Inverse polarity protection
The EC 20 flat with integrated electronics is protected against polarity rever-
sal of the supply voltage V
CC
. This means that the negative input voltage must
not exceed the maximum permitted supply voltage V
CC
.
6.2 Undervoltage switch-off
The power stage is switched off if the supply voltage V
CC
falls below approx.
8.5 V to prevent the EC 20 flat with integrated electronics operating off the
specification.
As soon as the supply voltage exceeds the restart threshold of approx. 9 V,
the EC 20 flat with integrated electronics is ready for operation.
6.3 Overvoltage switch-off
The power stage is switched off if the supply voltage V
CC
exceeds approx.
29.5 V to prevent the EC 20 flat with integrated electronics operating of the
specification.
As soon as the supply voltage falls below the restart threshold of approx. 28.5 V,
the EC 20 flat with integrated electronics is ready for operation.
6.4 Blockage protection
The power stage is switched off if the rotor is blocked continiously for more
than 2 seconds.
The EC 20 flat with integrated electronics automatically attempts to restart
after 4 seconds.
6.5 Temperature monitoring
The power stage is switched off if the PCB temperature exceeds approx. 100°C.
As soon as the PCB temperature has fallen below approx. 90°C, the EC 20
flat with integrated electronics is ready for operation.
6.6 Current limiting
The winding current is limited electronically to approx. 650 mA. The maximum
load torque is also limited accordingly.
If the motor shaft slows down completely due to current limitation, the blocka-
ge protection switches off after 2 s.
6.7 Overvoltage protection
The overvoltage protection comprises a bi-directional transzorb diode (over-
voltage protection diode) that can take a maximum peak energy of 150 mWs.
Continuous power loss is 1W. Threshold voltage is 36 V, independant of
polarity.
