about 737NG alternate flap extention

[sky-738]

today i flew a simulator lessen , i met a right eigine fire with DC bus 1 off.it took a system b failure to me , when i try to extend flap use the alternate flap switch , nothing happened ,looks like the motor is not move .my question is which bus is assoicate with the alternate flap motor?

[de facto]

The standby hydraulic Electrical motor driven pump is using 115 V AC,3phase 400HZ.
Moving the switch to ARM,will send 28V DC power to energize the stby pump relay.
This relay sends 115 V AC (transfer bus2) power to the standby hydraulic system Electric motor.

[Denti]

I think he was asking about the electric motor for the trailing edge devices, not the standby hydraulic for the leading devices.

@sky-738 sorry, can't really help you there as the documentation available to me does not specify which bus powers the alternate flap extension trailing edge motor. Sadly documentation has been dumbed down way too much, try to get hold of an AMM or similar documentation if you can.

[Yeelep]

The trailing edge flap electric motor is powered by the 115V AC xfer bus 1, through the alt.flap up and down relays, which are powered by the 28V DC bus 1.

[sky-738]

thanks Yeelep , it helps a lot