Changed fan motor.

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  #1  
Old 10-03-20, 03:27 AM
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Changed fan motor.

Hello everybody. This is my first A/C project although once welded a con rod on a compressor when I was at sea.
I am still waiting for the model number and make from the owner of the unit, but I changed the fan motor to a different synchronous ac type fan motor. When we first tried the unit, there was a wait and then everything started working normally. We were thrilled and proceeded to put things back where they were supposed to be. Switched on and found that the fan failure warning was blinking. The old fan is an ELCO Italian make 0.33A 230/240v is there any way to fool it into working?
 
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Old 10-03-20, 05:30 AM
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Have you tried disassembling everything back to the point where everything was working normally with the new fan motor? There is no way to fool an AC motor into working normally. It is possible the fan failure circuit is not compatible with the new fan motor resulting in a false positive. Also the voltage frequency could be an issue. Where are you located?
 
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Old 10-03-20, 05:50 AM
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I live in France and the unit is in Paris. Motor is 50 cycles The old motor had a 2 mfd capacitor while the new one does not have a starting cap.
 
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Old 10-03-20, 10:40 AM
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Welcome to the forums.

Since this is predominately a North American based site.... our help may be limited as our equipment is different than yours and we can't get service info on many of those units.

It sounds like your new motor may not have the needed power to start the blower wheel turning.
 
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Old 10-03-20, 10:53 AM
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The motor runs ok but somehow it does not start any more due to a diagnostic that was not there before. There is a blinking light that indicates a fault with the motor. It may have something to do with the absence of the 2MFD capacitor. IMHO
 
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Old 10-03-20, 10:58 AM
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You could can always post pictures of what you are working with..... How-to-insert-pictures.
If the motor only has two wires..... it won't use a capacitor.
 
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Old 10-03-20, 11:19 AM
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Is it possible that the absence of the capacitor that was in the original system might be "alerting" the monitoring system? Would adding the original capacitor affect the running of the new motor? It might be using the charge in the capacitor to generate a fault code.
 
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Old 10-03-20, 11:30 AM
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If your system is responsive to no air ....... it's more likely to be a sail switch that senses air movement as opposed to a circuit monitoring the motor.
 
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Old 10-03-20, 12:47 PM
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Sorry but there is no sail switch. I know what you mean though. This is definately a fault finding monitor.
 
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Old 10-03-20, 02:22 PM
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I would need to see a manual from that unit to offer any type of meaningful help.
I don't know of any unit here that monitors the actual motor for faults.
It's just too complicated and there is no reason for it.

The only time a unit needs to confirm airflow is if it uses electric heating coils and then it's typically a sail switch used.
 
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Old 10-03-20, 02:42 PM
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Thank you for the reply. I will wait for the details of the unit and get back to you. As soon as the unit is plugged in and the start button is pressed, there is a blinking light that indicates a fan fault.
 
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Old 10-03-20, 04:03 PM
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Your original motor was less than 1/10 horsepower. AC motors this small are shaded pole type and don't use a capacitor for starting torque as the loads are small so I am not aware of what the cap on the original motor was for. The motors are wound to rotate in a single direction. Remove fan from new motor. With the motor powered give the motor shaft a spin CW. If it continues to rotate, motor is good, however the fan is too big for the motor. If it doesn't rotate, give motor shaft a spin CCW. If it continues to rotate, motor is good, however the fan is too big for the motor. If it doesn't rotate, motor is bad.
 
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Old 10-04-20, 12:04 PM
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As you say, the new motor does not use a starting capacitor while the old one did use one. I think there were two coils in the old motor but it was not repairable. I really need to find a suitable motor that uses a 2mfd cap for starting.
 
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Old 10-07-20, 05:15 PM
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When you first powered the new motor and it ran normally (see first post) was the fan attached? If yes then you have done something during reassembly to increase load on motor. If no, you need a larger motor.
 
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Old 10-08-20, 04:14 AM
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The fan and motor is a self contained unit and still works, but not in the actual circuit. I have found an ac unit that has the same motor and hoping they can send it to me. Thanks guys.
 
 

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