Yaskawa E7L Drive Bypass - Manual (Page 110)

Programming 5 - 18
b2-02 DC Injection Braking Current
Setting Range: 0 to 100%
Factory Default: 50%
The level of DC Injection Braking Current affects the strength of the magnetic field attempting to lock the motor shaft.
Increasing the level of current will increase the amount of heat generated by the motor windings and should only be increased
to the level necessary to hold the motor shaft. DC Injection current is set in percentage of Drive rated output current. Drive
rated output current is stated on the Drive nameplate.
b2-03 DC Injection Braking Time at Start
b2-04 DC Injection Braking Time at Stop
Setting Range: 0.00 to 10.00 Seconds
Factory Default: b2-03 = 5.00 Seconds
b2-04 = 0.00 Seconds
b2-03 is one of the special parameter settings required by the Bypass logic circuit. See Table 5.1.
The Drive can be programmed to automatically DC Inject for a predetermined amount of time prior to accelerating to speed
(b2-03) and/or at the end of a Ramp to stop (b2-04). Parameter b2-03 can be used to stop a rotating motor prior to attempting
acceleration (i.e. a wind milling fan). If DC Injection braking at start or Speed Search is not enabled, attempting to Drive a
spinning motor may cause nuisance tripping.
Parameter b2-04 can be used to resist any residual motion of the load after the deceleration has finished.
Fig 5.7 DC Injection Braking During Starting and Stopping
Parameter b2-04 also serves the function of affecting the length of time DC Injection to stop (b1-03= “2: DC Injection to
Stop”) will occur.
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.
Output Frequency
DC injection
b2-03 b2-04