5V DC Motor

Hello,

I'm trying to make a project to run a 5v Brushless DC waterpump. I'm using an external power supply (5V) and a PN2222 transistor. The circuit is working great with a 3-6V DC Motor, but when I try to switch it to my 5V Brushless DC Pump it isn't working at all.

What I already tried doing:

  • test the waterpump directly to my 5V power supply (it works)
  • test my circuit with a regular dc motor (it works)

|500x386

Hello,

I'm trying to make a project to run a 5v Brushless DC waterpump. I'm using an external power supply (5V) and a PN2222 transistor. The circuit is working great with a 3-6V DC Motor (regular), but when I try to switch it to my 5V Brushless DC waterump it isn't working at all.

What I already tried doing:

  • test the waterpump directly to my 5V power supply (it works)
  • test my circuit with a regular dc motor (it works)

|500x386 (The two cables on the left go to the 5V powersupply)

Have You measured the voltage across the motor? The transistor will introduce a voltage loss that maybe affects the brushless motor harder then the 3 - 6 Volt motor. What is the spec for the brushless motor? Using a logic MOSFET transistor could improve things.

You didn't state the value of the base CL resistor. With the 1k pictured in Fritzing, you can only safely switch small loads (~50mA). A 2N2222, even with a low value base resistor (180-220ohm), shouldn't switch more than 200mA. If your pump draws more than that, then switch to a logic level mosfet. See the first diagram on this page. Leo..

The brushless motors that I am familiar with require a driver rather than just DC power. The motor itself has 3 wires.

Is this what you have?

No, mine has 2 wires.

I fixed it by using a 220ohm resistor, the pump is now running correctly. But is that safe enough? my pump is a 5v, 2.3w wich results in 0.46A? Or should i find another solution?

Wawa: You didn't state the value of the base CL resistor. With the 1k pictured in Fritzing, you can only safely switch small loads (~50mA). A 2N2222, even with a low value base resistor (180-220ohm), shouldn't switch more than 200mA. If your pump draws more than that, then switch to a logic level mosfet. See the first diagram on this page. Leo..

Okay, thanks for your help, the pump is now running correctly by using a 220ohm resistor.

But my pump is a 5v, 2.3W, wich results in 0.46A. Is it safe to keep my circuit with the 220ohm resistor or should i look for an other solution?

jefvdd: But my pump is a 5v, 2.3W, wich results in 0.46A. Is it safe to keep my circuit with the 220ohm resistor or should i look for an other solution?

Depends. A not fully saturated transistor has more voltdrop across, so your pump gets less, and the transistor gets hot. If you're happy with the pump speed, and the transistor doesn't get too hot... Leo..

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