Current sensors in parallel? Need 5V signal when fan(s) turn on.

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drewintoledo

Joined Apr 18, 2022
5
I will be building a tightly insulated house soon. Because of this, when I turn on exhaust fans I will need to introduce make-up air into the house.
I purchased a Fantec system model MUAS750. This system will energize and introduce additional air into the house when a signal is received on the controller pins. I've attached a wiring diagram.
It appears that the controller needs a 5V signal produced by a current sensor (Greystone model CS-650-10) to turn on the system which then opens the damper and energizes the fan. The current sensor is to monitor a power lead to the kitchen exhaust fan. My problem is that I need to monitor at least 3 different fans. These fans could all be turned on simultaneously but if that happens, I believe the current sensor would output much more than 5V.
A couple issues:
1.) I am testing the sensor on a small fan (Fantec model RVF4). When I turn the fan on I am only seeing .2V output from the sensor. I need 5V. I will try wrapping a couple turns of the line or neutral line in hopes it will output close to 5V.
2.) I need to monitor multiple fans but there is only one input on the controller. Is it possible to parallel multiple current sensors into the inputs on the controller? Or maybe I can run the line or neutral line from ALL fans through one current sensor and "clamp" the voltage with a Zener? Maybe some sort of logic device already exists for this purpose?
Please help.
 

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Ya’akov

Joined Jan 27, 2019
6,856
Welcome to AAC.

You need to create a logical OR gate. There are a few wants to do it How far away are the sensors from the controller that needs the signal?
 

Ya’akov

Joined Jan 27, 2019
6,856
The furthest distance would be no more than 50 feet away.
50 feet is a very long way for a small signal like a current transformer. You will probably have to do signal conditioning at the fan and send a definite signal to an OR gate whose output is connected to the controller.
 

eetech00

Joined Jun 8, 2013
3,418
I will be building a tightly insulated house soon. Because of this, when I turn on exhaust fans I will need to introduce make-up air into the house.
I purchased a Fantec system model MUAS750. This system will energize and introduce additional air into the house when a signal is received on the controller pins. I've attached a wiring diagram.
It appears that the controller needs a 5V signal produced by a current sensor (Greystone model CS-650-10) to turn on the system which then opens the damper and energizes the fan. The current sensor is to monitor a power lead to the kitchen exhaust fan. My problem is that I need to monitor at least 3 different fans. These fans could all be turned on simultaneously but if that happens, I believe the current sensor would output much more than 5V.
A couple issues:
1.) I am testing the sensor on a small fan (Fantec model RVF4). When I turn the fan on I am only seeing .2V output from the sensor. I need 5V. I will try wrapping a couple turns of the line or neutral line in hopes it will output close to 5V.
The datasheet indicates the current sensor is an analog device. So I would expect its 0-5v DC output to be scaled based on the "sensed" input current. That may be why you are only seeing 0.2v output (there isnt much current draw by the test FAN).

If analog inputs from multiple FANs, you'll need to detect the analog input level and convert to a DC logic output level (comparator) to produce an on/off type signal.
 

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LowQCab

Joined Nov 6, 2012
2,644
The simplest way to do this is to use 3 small Switching-Power-Supplies like these ..........
https://www.digikey.com/en/products/detail/mornsun-america-llc/LD03-23B05WR2/13968647

They're only 1" square, and have 4000-Volts of isolation.
The Outputs can be connected in parallel without problems,
so if one, or all 3 turn on, it's still just a 5-Volt Output to the Controller-Input.
They simply need to have their input connected to the Motor-Power-Leads that You want to monitor.
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