The Questions about ELC-08D3R3E Fixed Inductor

Hello all. Thank you for taking time to read my post.

I would like to ask a question about ELC-08D3R3E fixed inductor--5V by using uln2003.

My schematic diagram is given below.I have add the pull-up resistance and the wiring are no problems. But I really don’t know why can’t relay pick up?
Can anyone help me ? Thank you a million.

Now two questions arose: (while I believe I get the point that this is how the reactive power is controlled while functioning as a normal rectifier for active power control, i.e. frequency control)

1. Inductance for high power rating are very expensive - why exactly do we find 1-Generator 1-Phase designs where the inductances are omitted? Or rather: Why do we need this inductance for filtering, buffering of reactive power here in the mentioned ELC design? Is it related to the 2-generator configuration? Is it because of the 3 phases? Is it possible to omit or replace their function?
2. The working principle of the PWM dump loading is that we rectify the power the generators produce and no load currently needs. This task is solved by a Voltage Source Converter (VSC). The question arises if it is possible to go with Rectifier Diodes instead as simplification?

@2. Currently I can't see why not other than that some special power component is being controlled by this VSC or probably because diodes are not suitable for 5..20kW power range?