PWM Fan ramps up to 90% than goes to 10%

[xReM1x]

Hi, I got the PFC1212DE From eBay, at first, i connected the fan with the connector and the fan worked great.
Than I removed the connector (I dont need the connector) and soldered some wires, I tried turning the fan and the fan ramps up to 90% than goes to 10%.
Whats the problem? Do i have to use PWM or something?
If yes, how did the fan worked first without PWM?
It happend to me too at other delta fan (PWM).
wtf?

 

[diegobb]

It's the power source capable of delivering the 4 Amps that the fan requires?
In the datasheet says that "With control signal lead disconnected, the fan will spin at maximum speed". It also says "Start at low speed, after 10 sec running at full speed".

Best regards

 

[xReM1x]

It's the power source capable of delivering the 4 Amps that the fan requires?
In the datasheet says that "With control signal lead disconnected, the fan will spin at maximum speed". It also says "Start at low speed, after 10 sec running at full speed".

Best regards

The power supply can deliver 10A.

 

[xReM1x]

Problem Solved.
25kHz PWM Controller did the job.