78 Program featuresPre-heating (Motor heating)The pre-heating function keeps the motor warm and prevents condensation inside themotor by feeding it with DC current when the drive has been stopped. The heatingcan only be on when the drive is in the stopped state, and starting the drive stops theheating.When pre-heating is activated and the stop command is given, pre-heating startsimmediately if the drive is running below the zero speed limit (see bit 0 in parameter06.19 Speed control status word). If the drive is running above the zero speed limit,pre-heating is delayed by 60 seconds to prevent excessive current.The function can be defined to be always active when the drive is stopped or it can beactivated by a digital input, fieldbus, timed function or supervision function. Forexample, with the help of signal supervision function, the heating can be activated bya thermal measurement signal from the motor.The pre-heating current fed to the motor can be defined as 0…30% of the nominalmotor current.Notes:• In applications where the motor keeps rotating for a long time after the modulationis stopped, it is recommended to use ramp stop with pre-heating to prevent asudden pull at the rotor when the pre-heating is activated.• The heating function requires that the STO circuit is closed or not triggered open.• The heating function requires that the drive is not faulted.• Pre-heating uses DC hold to produce current.Settings• Menu - Primary settings - Motor - Pre-heating• Parameters 21.14 Pre-heating input source and 21.16 Pre-heating current (page151). Energy optimizationThe function optimizes the motor flux so that total energy consumption and motornoise level are reduced when the drive operates below the nominal load. The totalefficiency (motor and drive) can be improved by 1…20% depending on load torqueand speed. Energy optimization is enabled by default.Note: With permanent magnet and synchronous reluctance motors, energyoptimization is always enabled.Settings• Menu - Energy efficiency• Parameter 45.11 Energy optimizer (page 233).
