Not enough power for motor and driver

T Chap

I had been driving a brushless 23 size motor easily with a custom driver board, using ON MC33035 feeding HIP4086. Now I am trying to drive a much larger 34 motor and the MC33035 is faulting out. I was told by the ON semi app engineer that I may be getting too much ripple on the lines with the larger motor under load. The motor supply is unregulated directly off this transformer below, the front end and back end are tied together, it feeds a 6amp bridge rectifier, 2200 uf and a few smaller caps.

Would tying two supplies together after the bridge rectifiers be a simple solution to fix the voltage drop and possible ripple? There is a fast blow 2amp on the AC in, it does not pop under heavy load. A 2 amp fast blow does pop on the motor driver PCB under load, but a 3amp slow does not pop under load. The transformer below is rated at 18 VAC @ 2.8A with the unloaded output somewhere around 27VDC.

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I am thinking to first to get more power, but prefer to use existing boards and parts, just double up rather than add external parts.

Any thoughts welcome on if this will work to beef it up.

kwinn

Hard to be sure exactly how you have this wired up without a schematic but I am guessing you feed the motor from the DC output immediately after the bridge rectifier. I have done that fairly often and in most cases find that putting a diode between the power supply input filter capacitor and the point where the motor is connected takes care of this kind of problem. The diode prevents the capacitor from discharging rapidly when the motor draws a large momentary surge of current.