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hello , does anyone know , how the 10 volt dc supply is needed to run the motor , and is there anyway to run the motor without it , I seem to have a few problems with this type of motor , normally the searl ones , any information would be helpful thanks
Hi,
10v (or more correctly 0 to 10v) is for speed control - they are variable speed fans.
Pretty sure fixed speed units also available (straight 240)
sorry was not really the information I was asking for . I was wanting more detail
They are called EC fans. They normally give a 10 or 20 v DC output which can be linked to the input terminal to make them run at full speed.
Google EC fans
Hi billy7
The EC fans your using are variable speed fans to control the speed of the fans to control a constant system discharge pressure.
The fans are connected to the 240 volt supply voltage, but then need a 0--10volt dc signal to actually cause the fan to run at a certain speed,say 14Bar on R404A.
But you need a controller that gives out a 0--10volt.
For example the Danfoss pack controller AK PC 530 has up to 8 compressor steps (Compressors and Unloaders) it also has a 0--10dc output for the condenser control .This 0--10 volt signal is connected to the EC fans. At 0 volt the fan is stopped at 10volt the fan is at full speed 1500RPM, at 5 volt the speed would be 750 RPM.
This 0--10 volt will vary as the demands of the condenser changes. So the condenser needs to have a pressure transmitter fitted to it connected back to the PC 530 controller.The pressure range of the pressure transducer is then entered into the memory of the controller .A typical transducer range maybe for instance be 0--20Bar. So the range of the transducer you fit is entered into the controllers menu for the condenser control. Minimum transducer range = 0 Bar ,Maximum transducer range = 20 Bar in this case. So then you set the condenser control set point into the controller menu, say 15 Bar
So now when the plant runs the discharge pressure starts to rise ,the transducer registers the increase in pressure back to the controller ,the controller then changes the 0--10 Volt output signal voltage to the dc fans accordingly.
So we have a pressure transducer with a range of 0--20Bar
So our controller will give out 0volt at 0 Bar and 10volt at 20 Bar
Our condenser set point pressure is 15Bar
So the dc output would in theory modulate around the 7.5volt to keep the discharge pressure constant at the 15 Bar pressure.
That is putting it in simplistic terms but obviously ambient air temperature,condenser size,compressor load etc will all have a bearing on the fan speed but the 0--10 Signal will vary to vary the fan speed to keep the discharge as close to the 15 Bar set point as possible.
This gives stable condenser pressure ,stable liquid supply pressure and a more stable expansion valve operation.
You can get a 0--10 variable battery powered power supply which you could connect to the fans 0--10volt supply and you could control the speed of the fans by winding the power supplies potentiometer up and down for testing purposes or you could simply fit a 9volt battery to the same connections and the fan would then simply run at 90% spfull load speed.
All of the Controls manufacturers, manufacture pack controllers with these 0--10volt o/ps some have 2 0--10volt O/ps ,one for speed controlling the lead compressor via a suction pressure transducer and the other for speed controlling the condenser fans.
EC fans have an inbuilt invertor control ,whereas normal fans to be speed controlled would require an external invertor drive which may have a cost disadvantage.
The Use of EC fans is becoming the norm as huge energy savings can be achieved by using investors on condenser fan control, typically running fans at half speed via an invertor will reduce the fans current consumption down to approx12.5% of the full speed consumption as the fans
Hope that helps .if you need to discus let me know