I'm controlling the ceiling fan speed by using triac when the fan is rotated at full speed by triggering the gate via moc3021(triac based), diac and cap circuitry the fan is rotating at a full speed but when i remove the gate of moc3021 even though the fan is rotating at a full speed without gate hence there is no control on gate of triac when high current flows.

So please suggest something where i can control the gate of moc3021 for high current flow.
here is the circuit diagram

(Moderator's note: Please do not type in all capital letters -dc)

 

I suspect that the reason is leakage through the MOC3021 even when it is switched off. The only place any such leakage can go is through the diac. Put a resistor across C4.

BTW your circuit shows C4 and C5 as electrolytic types though they will have an AC voltage across them and so they will have a short life. Those capacitors need to be non-polarised types.

 

What is the purpose of the diac? This is not required for MOC3021 use.
See Fairchild AN-3006 for MOC3021 interface method.
Max.