amat_24
03-11-2014, 08:09 AM
Good day everyone.
I'm currently in the process of exploring the VRF technology in preparation for working in VRF sales
(my background in in water chillers).
I've done some reading and questioning here and there, and been able to learn alot
However, there has been a topic regarding the VRF that no one has given me a clear answer to. Not the internet, not the product manuals, and certainly not the engineers already working in the VRF business. And I was hoping that someone here would be kind enough to explain this to me:
Is the compressor motor type AC or DC????
Now, I know that all VRF manufacturers market their product as "DC inverter compressor" based
But isn't an inverter a device that converts DC to AC (PWM, but still perceived as AC)? Doesn't this make the motor itself AC, and the DC is merely used to produce AC of controllable frequency (and therefore controllable motor speed).
I took a look at a power wiring diagram of a VRF module and it looked exactly like this:
3-ph power -> 3-ph bridge rectifier -> (now DC power) -> capacitor and inductor to smoothen the ripple -> Inverter module (IGBT's) -> Motor (3 wires)
This looked to me exactly like the VSD/VFD configuration
Does this mean that the "DC inverter compressor" is pretty much just a compressor driven by an AC motor thats modulated by a VSD?
If so, why don't they market it as VSD? (technically correct term, already well known in the market)
Also, I recall reading somewhere that the VRF compressors include a permanent magnet, which means that they are NOT induction motors.
If this is true, then what kind of motors are they?????
The same applies to condenser fans. The manuals claim that they are DC to enable speed control, but are they?
Looking forward to your help! :o
I'm currently in the process of exploring the VRF technology in preparation for working in VRF sales
(my background in in water chillers).
I've done some reading and questioning here and there, and been able to learn alot
However, there has been a topic regarding the VRF that no one has given me a clear answer to. Not the internet, not the product manuals, and certainly not the engineers already working in the VRF business. And I was hoping that someone here would be kind enough to explain this to me:
Is the compressor motor type AC or DC????
Now, I know that all VRF manufacturers market their product as "DC inverter compressor" based
But isn't an inverter a device that converts DC to AC (PWM, but still perceived as AC)? Doesn't this make the motor itself AC, and the DC is merely used to produce AC of controllable frequency (and therefore controllable motor speed).
I took a look at a power wiring diagram of a VRF module and it looked exactly like this:
3-ph power -> 3-ph bridge rectifier -> (now DC power) -> capacitor and inductor to smoothen the ripple -> Inverter module (IGBT's) -> Motor (3 wires)
This looked to me exactly like the VSD/VFD configuration
Does this mean that the "DC inverter compressor" is pretty much just a compressor driven by an AC motor thats modulated by a VSD?
If so, why don't they market it as VSD? (technically correct term, already well known in the market)
Also, I recall reading somewhere that the VRF compressors include a permanent magnet, which means that they are NOT induction motors.
If this is true, then what kind of motors are they?????
The same applies to condenser fans. The manuals claim that they are DC to enable speed control, but are they?
Looking forward to your help! :o