Moving wire over a Square Frame!

$ABCD$ is a square frame made from different wires of same length and each having different uniform resistance per unit length. Resistances of wires forming sides $AB, BC, CD$ and $DA$ are $100W, 400 W, 500 W$ and $200 W$ respectively. An ideal cell is connected across $B$ and $D$ . A straight conducting wire containing a resistance and a galvanometer in series starts rotating about pivoted point $A$ from initial position as shown with uniform angular velocity $\omega = \frac{\pi}{360} rad/sec$ . One end of the straight wire (rotating) is pivoted at $A$ and other end always in sliding contact with a side of the square. The time (in seconds) after start when galvanometer shows zero deflection is?