I have installed two Hampton Bay 60" Industrial Ceiling Fans (Model # 158 987) on the same electrical circuit. Unfortunately, I had installed the circuit before I purchased the fans. I now find that the 4 speed fan switch is not strong enough to properly operate both fans. They spin on the two fastest settings but not on the two slowest. The switch is rated at 1.25 amps. I tried installing a 5 amp variable switch, however when operating the fans made a very loud humming noise.
Any other suggestions?

I have installed two Hampton Bay 60" Industrial Ceiling Fans (Model # 158 987) on the same electrical circut. Unfortunately, I had installed the circut before I purchased the fans. I now find that the 4 speed fan switch is not strong enough to properly operate both fans. They spin on the two fastest settings but not on the two slowest. The switch is rated at 1.25 amps. I tried installing a 5 amp variable switch, however when operating the fans made a very loud humming noise.
Any other suggestions?
... switch something of a light dimmer type rheostat? If so, the humming is probably quite normal due to the nature of the internal circuits. These 'dimmers' also are noisy when used on lights.