Jetter JetMove 208-480, User Manual, Page: 45 / 124

JetMove 208-480 5.2 Motor Protection
Jetter AG 45
5.2.3 Motor Overload Protection to UL
The UL standard prescribes a motor overload detection for a servo amplifier that
meets the following points:
The "trip current" is defined to be 1.15 times the user-set continuous rated current.
• If the average motor current corresponds to the trip current, the overload
protection has to switch off the motor after a limited time
• If the average motor current is 2 times higher than the trip current the overload
protection has to switch off the motor after at least 8 minutes.
• If the average motor current is 6 times higher than the trip current, the overload
protection has to switch off the motor after at least 20 seconds.
This protection (error message 31 will occur) can be parameterized only through the
nominal current value.
The motor overload protection is always active and cannot be deactivated.
NOTICE
Because of the fact that after reset the I²t calculation always starts at zero, the
motor overload calculation is wrong if the motor is already hot when the digital
servo amplifier JetMove 204-480 is switched on (that is, when parameterization
of I²t calculation is completed and 24 V logic power supply is applied).
Therefore wait until the motor is cold before enabling the axis again.