Hi,
Generating more EMI due to BLDC motor
Not the motor is the problem, but the control unit.
1. Whether 100ohm gate resistor is suitable for 30kHz switching frequency ?
There is no general rule, thus it's hard to say.
Btw: Your fastest switching edge will be the switch OFF edge .... without the 100R in series.
If i'm changing Gate resistor or Switching frequency can help me in EMI reduction?
Most probably yes. The easiest may be to modulate the switching frequency a bit --> spread spectrum.
2. 63Mhz is 2000 times the switching frequency. considering this switching circuit will create this much multiplied noise ?
Obviously it will be the cause. An ideal square wave consists of infinitely high frequencies but with decreasing amplitude.
The problem will be some resonances...on the PCB, the wiring...
3. Blower is the load. Is this one as EMI source ?
As already said. I assume not, because a BLDC motor is a passive device, it can't generate high frequencies.
4. Without running the blower EMI is within limit(Standby condition, only microcontroller is in ON state), hope microcontroller internal oscillator will not create any EMI source. My assumption is correct ?
Maybe. Maybe PCB layout, maybe just some accidental interference, maybe the power supply...
Parallely, I'm looking into wire routing, PCB layout and component placement.
Yes, you could have posted some pictures.
I see a lot of guessing from your side. Why? Why don't you do some measurements. A narrow 63 MHz filter, a suitable scope...and you are able to check node by node...
Or simple test with a ferrite across the motor wires, or a shielded cable...
63MHz ... is about 4.75m wave length.
Or 2.38m lambda/2
Or 1.19m lambda/4
Is your cable length equal to one of these lengths?
Klaus