Results 1 to 11 of 11
Thread: Speed control of the compressor
-
09-12-2007, 09:44 AM #1
Speed control of the compressor
Further to the thread Cheap Inverter Checker in another section, I have some questions for those having some knowledge of the electronic power PCB's in airco's.
Varying the speed with an industrial VFD is known (like Danfoss, Telemecanique, GE, ..)
We use those often on racks/packs.
More specific, how's the speed controlled in the latest Daikin and Mitsubishi Electric compressors? These are DC compressors, is this right?
On both units, you have a power control module which controls the speed of the compressor. Does someone know what type of signal is given to regulate the speed?
For a test, I want to use an external signal which I control myself connected to the Power PCB to play with the speed of the compressor from a Daikin and a Mitsubishi.
This is not for a common airco application. If I destroy it due to a too high or too low speed, then that's my problem.
On a Daikin VRV, they increase speed to - I think - 250 Hz (so this can't be a DC motor because you vary the voltage to the stator and the rotor)
Is this the same for a Mitsubishi?
Does someone know a link explaining the technique of varying the speed of the compressor on modern compressors?
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
-
09-12-2007, 09:57 AM #2
Re: Speed control of the compressor
I'm speaking about the smaller units till 7 to 9 kW.
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
-
09-12-2007, 10:46 AM #3
Re: Speed control of the compressor
Found a general link for the Daikin product http://www.freepatentsonline.com/20060103342.pdf or posted at http://download.yousendit.com/DD9C548A38B65366
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
-
09-12-2007, 10:47 AM #4
Re: Speed control of the compressor
A schematic of the internal of the compressors should also be fine.
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
-
09-12-2007, 11:34 AM #5
Re: Speed control of the compressor
For those interested in electronics, a good link http://www.maxim-ic.com/tarticle/article.cfm#2
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
-
09-12-2007, 03:48 PM #6
Re: Speed control of the compressor
Japan factory enginners try to keep as much technical detail secret to slow down the coppiers in places like china & Korea.
Diakin & Mitsubishi still use 3 phase compressor motor in VRV / VRF products. But the motors are confusingly called D/C motors. But I think that is short for digitally comutated or some such fancy name. The VRF systems still use inverters to generate 3ph to the compressor at veriable hz.
But I think the windings are optamised for inverter slow ramp up start zero to 30 hz. Because if you connect 3ph 50 hz direct to the compressor it draws a massive amps & trips the power supply mcb. But again dont expect to get any technical data for the motor windings unless do dont mind being suspected as industial spy.
-
09-12-2007, 10:45 PM #7
- Join Date
- Sep 2007
- Location
- Split Croatia
- Age
- 57
- Posts
- 6,151
- Blog Entries
- 6
- Rep Power
- 36
Re: Speed control of the compressor
Download this RAR and extract. You (and others) wil find there Poverpoint presentation that explain some of yours questions.
http://www.mediafire.com/?6jklhym2mcg
-
09-12-2007, 11:36 PM #8
- Join Date
- Sep 2007
- Location
- Split Croatia
- Age
- 57
- Posts
- 6,151
- Blog Entries
- 6
- Rep Power
- 36
Re: Speed control of the compressor
This is not true as you may see from presentation I posted.
IPM circuit regulate maximum current, therefore there is no need to "windings optimization". When rotary compressor starts with low frequency, resistance to the turning is little, as a result current is smaller, and how the frequency become larger also resistance to the turning is larger and also current of compressor.
-
18-12-2007, 07:14 AM #9
Re: Speed control of the compressor
DC is a short form for BLDC (BrushLess DC Motor). These are in fact synchronous motors, but they are called DC because the motor and its inverter act just like a permanent magnet DC motor in which the collector and brushes are replaced by an electronically commutation device (inverter) .
Inside the motor, on the shaft, there are 3 hall sensors which tells the inverter when to commute the current into the appropriate phase. This hall sensors and the inverter replaced the collector.
-
18-12-2007, 07:28 AM #10
-
19-12-2007, 07:51 AM #11
- Join Date
- Sep 2007
- Location
- Split Croatia
- Age
- 57
- Posts
- 6,151
- Blog Entries
- 6
- Rep Power
- 36
Similar Threads
-
Testing Inverters
By fridge doctor in forum Air ConditioningReplies: 38Last Post: 15-06-2011, 06:52 AM -
Voltage control to control speed of single phase motors
By Pud in forum ElectricalReplies: 15Last Post: 17-04-2009, 03:50 PM -
Frick Quantum LX Compressor control panel: Capacity Control Screen
By screw_geek in forum Industrial CompressorsReplies: 17Last Post: 15-06-2008, 06:47 AM -
Thermo King OptiSet
By REEFER-TEK in forum TransportReplies: 4Last Post: 06-12-2007, 07:23 PM -
New Capacity Control Solution
By embrown in forum New TechnologiesReplies: 19Last Post: 30-12-2003, 01:33 PM