Yaskawa P7 Drive User Manual - Manual (Page 95)

Programming 5 - 11
b2-09 Motor Pre-Heat Current
Setting Range: 0 to 100%
Factory Default: 0%
A DC current can be circulated within the motor windings while the motor is stopped. The current will produce heat within the
motor and prevent condensation. Parameter b2-09 determines the percentage of Drive rated output current that will be used for
the motor pre-heat function. This function can be useful in applications where the motor sits for extended periods of time in
humid conditions. Motor pre-heating can only be initiated by closing a digital input programmed as a Motor Pre-heat
Input (H1-0x= 60). Check with the motor manufacturer to determine the maximum acceptable current level the motor can
withstand when stopped. Be sure not to exceed the motor manufacturers recommended level.
b3 Speed Search
The Speed Search function allows the Drive to determine the speed of a motor shaft that is being driven by rotational inertia.
Speed Search will allow the Drive to determine the speed of the already rotating motor and begin to ramp the motor to a set
speed without first having to bring it to a complete stop. When a momentary loss of supply power is experienced, the Drive
output is turned off. This results in a coasting motor. When power returns, the Drive can determine the speed of the coasting
motor and start without requiring it to be brought to minimum speed. Speed Search can be programmed to always be active by
setting b3-01 or it can be commanded by remote contact closure by setting a digital input.
There are two forms of Speed Search in the Drive, the speed estimation method and the current detection method.
Parameters L2-03 and L2-04 also affect the current detection method of Speed Search operation.
b3-01 Speed Search Selection
This parameter is effective only when the Drive is given a new “RUN” command.
Speed Estimation: Method (b3-01= 0 or 1) The speed estimation method will calculate the speed using measurements of
residual motor fields. The speed estimation version is bi-directional and will determine both the motor speed and direction. To
enable speed estimation Speed Search at start, set b3-01= “1: SpdsrchF Enable”.
IMPORTANT
When setting the Drive for remote Speed Search input, via a contact closure, the method of Speed Search
is determined by the setting of b3-01. If b3-01= “0: SpdsrchF Disable” then the remote input will initiate
speed estimation method, and if b3-01= “2: SpdsrchI Disable”, then the remote input will start the current
detection method.
Setting Description
0 SpdsrchF Disable
1 SpdsrchF Enable
2 SpdsrchI Disable (factory default)
3 SpdsrchI Enable
IMPORTANT
If the speed estimation method of Speed Search is to be used, then Auto-tuning must be performed prior to
using Speed Search. If the length of cable between the Drive and motor is ever changed after Auto-tuning
then Auto-tuning should be performed again.