Delta Fan Part Numbers


Active Member
Jan 3, 2012
Hi all,

Does anyone have a reference or know how to decode the suffix for Delta fan part numbers? I'm trying to replace a fan in a switch and even though the major part number is the exact same, the fans behave differently. The part number guide on Delta's website shows how to decode the main number, but just has the R and F suffix numbers for rotor lock and frequency (tach) output models.

For example, the original fan is a Delta FFB0412SHN-TYSC and I'm trying to replace it with a Delta FFB0412SHN-9C72. These are both 40x40x28mm 13k RPM 4-pin fans, however the replacement spins about 2k RPM faster when the switch is idle than the original and still good fans. At full speed all fans (old and new) spin at 13k, when the switch ramps down the fan speed the originals run at 5k, but the 9C72 spins at 7k. I can hear and feel that the new fan is spinning faster.

I have hooked both fans up to my meter, connected to a (weak) 12v battery and the tach output is the same on both fans at 400hz. (400/2) * 60 = 12,000RPM. It appears that the PWM input curve may be different between the two as when I short the PWM input to ground on the TYSC fan the rotor stops, but when doing the same on the 9C72 fan the rotor still spins at a very low speed.

It seems like there are so many different options (PWM curve, soft start, etc.) that one can order, but nowhere can I find a way to decode these numbers.