PC Chassis fan

[St1ckMan]

Hi all!
Posted this originally in VR-Zone but no replies.I need some advice with regards to hooking up more chassis fan to a motherboard with limited Fan connectors.

I have got a ASRock H170M-ITX/ac mobo and a ThermalTake F1 Suppressor chassis.

The mobo has got 1 chassis fan connector (4-Pin) already hooked up to a 120mm fan that came with the chassis. I am looking to hook up 2 rear exhaust 80mm fan but there is no more fan connectors.

I did some research on the internet and there is a "3-pin Y splitter". Link HERE

https://www.google.com.au/search?q=...=VcN-WPjdMoGi0gSMwqboBA#imgrc=A70T3Zr6jUIG2M: My idea is to hook up the 2x 80mm fan to the Y splitter connected to the sole chassis fan connector while I will hook up the 120mm fan using a 3-pin to molex.

Not sure how feasible it is but it will be great if someone can share their experience in this.

Thanks in advance!

 

[shadow84]

Your mobo comes with 2x fan headers.

- 1 x TPM Header
- 1 x Chassis Intrusion Header
- 1 x CPU Fan Connector (4-pin) (Smart Fan Speed Control)
- 1 x Chassis Fan Connector (4-pin) (Smart Fan Speed Control)*
- 1 x 20 pin ATX Power Connector
- 1 x 4 pin 12V Power Connector
- 1 x Front Panel Audio Connector
- 1 x USB 2.0 Header (Supports 2 USB 2.0 ports) (Supports ESD Protection (ASRock Full Spike Protection))
- 1 x USB 3.0 Header (Supports 2 USB 3.0 ports) (Supports ESD Protection (ASRock Full Spike Protection))

Connect your heatsink fan to the cpu fan connector. Then, get a 3-way splitter and connect all fans with it. It will then be connected to the chassis fan connector.

 

[St1ckMan]

Your mobo comes with 2x fan headers.



Connect your heatsink fan to the cpu fan connector. Then, get a 3-way splitter and connect all fans with it. It will then be connected to the chassis fan connector.

Thanks for the reply.
A couple of question:
1- Why not hook up the 120mm fan to the molex-3pin connector?
2- Can the voltage (hence the speed of the fan) be adjusted using the 3-pin 3way splitter?

 

[BrightBrightSun]

Thanks for the reply.
A couple of question:
1- Why not hook up the 120mm fan to the molex-3pin connector? (
2- Can the voltage (hence the speed of the fan) be adjusted using the 3-pin 3way splitter?

1. because by connecting it using the molex - 3pin connector you cant adjust the speed unless you use a voltage resistor

2. yes

 

[lalalalalala]

Thanks for the reply.
A couple of question:
1- Why not hook up the 120mm fan to the molex-3pin connector?
2- Can the voltage (hence the speed of the fan) be adjusted using the 3-pin 3way splitter?

1) Molex connector means ur fan will run at 100% speed all the time.

2) Yes as long as it is connected to the motherboard header

Sent from OnePlus A0001 using GAGT

 

[commach]

1. because by connecting it using the molex - 3pin connector you cant adjust the speed unless you use a voltage resistor

2. yes

Wrong way of speed adjustment using voltage resistor.

When you decrease the voltage, the current go up and burn the fan with overwhelming current.

 

[BrightBrightSun]

Wrong way of speed adjustment using voltage resistor.

When you decrease the voltage, the current go up and burn the fan with overwhelming current.

what i mean is like the fan speed reducer that noctua provides. maybe wrong term used

cant post images and links

 

[commach]

what i mean is like the fan speed reducer that noctua provides. maybe wrong term used

cant post images and links

Those are PWM controller, not voltage resistor.

A common misunderstanding of PWM and voltage resistor, PWM is controlling the fan using duty cycle, not reducing the voltage. Although is seem like the voltage indeed dropped when the fan spin at the lower speed, but actually it's still the same voltage but our MM are not fast enough to correctly detect the voltage.

 

[BrightBrightSun]

Those are PWM controller, not voltage resistor.

A common misunderstanding of PWM and voltage resistor, PWM is controlling the fan using duty cycle, not reducing the voltage. Although is seem like the voltage indeed dropped when the fan spin at the lower speed, but actually it's still the same voltage but our MM are not fast enough to correctly detect the voltage.

now i got it! thanks for explaining!

 

[Diaborex]

Wrong way of speed adjustment using voltage resistor.

When you decrease the voltage, the current go up and burn the fan with overwhelming current.

So is speed fan killing my fan?? I use it control my fan speed via 3pin

 

[commach]

So is speed fan killing my fan?? I use it control my fan speed via 3pin

PWM is not exclusive to 4 wires fan, if you are using 3 wires fan with PWM controller, you are fine, no issue. The 4 wires are assigned as follow:

1 GND Black
2 12V Yellow
3 Sense (Tach.) Green
4 Control (PWM) Blue

Using 3 wires simply meant you are not using the sensor pin. Without the sensor pin, you can't read the RPM, nothing to worried.

In fact, I'm using PWM controller to controller DC motor (or fan) with 2 wires only, without sensor, just VCC and GND.

 

[St1ckMan]

Thanks guys.
I will go check to see if SLS sells that splitter.

 

[jtjt00]

Thanks guys.
I will go check to see if SLS sells that splitter.

.
Try Cybermind at 4th floor.

 

[Diaborex]

PWM is not exclusive to 4 wires fan, if you are using 3 wires fan with PWM controller, you are fine, no issue. The 4 wires are assigned as follow:

1 GND Black
2 12V Yellow
3 Sense (Tach.) Green
4 Control (PWM) Blue

Using 3 wires simply meant you are not using the sensor pin. Without the sensor pin, you can't read the RPM, nothing to worried.

In fact, I'm using PWM controller to controller DC motor (or fan) with 2 wires only, without sensor, just VCC and GND.

Good to know.

So how do i know if I'm using a PWM Controller?
I know there's external PWM fan controller but is the on-board motherboard 3pin with built-in PWM controller or not?

Pardon me.
Thanks in advance!

 

[commach]

Good to know.

So how do i know if I'm using a PWM Controller?
I know there's external PWM fan controller but is the on-board motherboard 3pin with built-in PWM controller or not?

Pardon me.
Thanks in advance!

If you are able to control the fan speed manually and the fan still working till now, no mistake, you are using PWM controller. If using so called voltage resistor or dimmer, the fan already fried due to overwhelming current.

 

[wwenze]

Once upon a time, 3 pin fans with RPM reporting could be controlled by motherboard. Through what method, can you guess?

 

[lalalalalala]

Good to know.

So how do i know if I'm using a PWM Controller?
I know there's external PWM fan controller but is the on-board motherboard 3pin with built-in PWM controller or not?

Pardon me.
Thanks in advance!

In general all mobo headers are pwm Basically if u can adjust the speed, its pwm

Sent from OnePlus A0001 using GAGT

 

[wwenze]

In general all mobo headers are pwm Basically if u can adjust the speed, its pwm

Sent from OnePlus A0001 using GAGT

Yup.

Unfortunately the birth of the 4-pin fan screwed up the public understanding. Oh the power of marketing.

So for the record to clear things up,

3-pin fans were the norm as far back as the Pentium days. At around Pentium 3 era, temperature monitoring, fan speed monitoring, and fan speed control became a thing. Note that 3-pin fans are still getting used.

How they do this, is to perform PWM directly on the V+

During the Prescott era, Intel introduced the 4-pin fan, with the additional PWM control pin.

The difference is that, with 4-pin fans, the V+ is constant, while the PWM control pin controls the... erm... PWM

The motivation behind this is that, many 3-pin fans are actually not well-suited for PWM. Like making weird ticking sounds for example. Reason is that DC brushless fans actually have built in electronics (inverter, protection), and they prefer to have a constant voltage. Another issue is that switching a big load incurs huge current swings and switching losses at the interfaces, so switching frequency is limited, which aggravates the first problem.

With a 4-pin fan, the fan electronics get a constant V+, and switching of load is done at the fan; the PWM wire supply the signal which sees a high resistance load, hence it's a low current connection with less losses. Both factors make higher switching frequencies possible.