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Issue No. :- TC-77040725Dated :- 8th July, 2004 TECHNICAL BULLETIN

Product : Multi-V, Multi, Inverter Frequency : 50/60 HzCategory : Information/Technology

Fig 1 : Construction of EEV

Construction :It consists of pulse motor which is controlled by microprocessor.•A needle for opening and closing the the orifice space.•A spring for backing force for needle.•Flow in and flow out connected pipes. (fig1)

Principle : The amount of refrigerant flow is varied on the basis of load on the evaporator. In other words it control the mass flow rate on the basis of temperature at different locations.

Title: Electronic Expansion Valve (Linear expansion valve)

Details : Also known as linear expansion valve. Definition : It is very dynamic expansion device used for bringing down the condensing pressure to evaporating pressure and also control the mass flow rate of the refrigerant flowing in the system. It is very precise and accurate device which can react instantaneously to any kind variation or abnormality occurs during air-conditioners working.

Motor

Needle

Orifice

Flow in

Flow out

Shaft

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Issue No. :- TC-77040725Dated :- 8th July, 2004 TECHNICAL BULLETIN

Pulsemotor

Working : Temperature sensors are provided at different locations in evaporators and condenser such as inlet, outlet & middle.All this data is gathered and is send to the microprocessor a feedback loop. It calculates the optimum mass flow of refrigerant, depending on that a signal is sent to regulate the valve’s opening and closing (Fig 2).

Benefits : Wide capacity range.•High cool down capacity.•Quick response.•Less energy consumption.•Bi-flow capabilities.•Accurate and precise control.•High resolution.

Fig 2 : Working of LEV

Fig 3 : Actual shape of LEV

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Issue No. :- TC-77040725Dated :- 8th July, 2004 TECHNICAL BULLETIN

Usage : Multi Split systems, Variable refrigerant flow air Conditioning systems,Multi-V, Multi-V plus, Multi-V sync, DC inverter and MPS variable and MPS inverter systems.

Wiring connections : There are 5 wires of different colors to control the excitation of the motor. Depending on the the phase active and the time of pulse it decides the angle of motor to rotate. Below is the graph showing the phase excitation.

Drivingcircuit

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Issue No. :- TC-77040725Dated :- 8th July, 2004 TECHNICAL BULLETIN

Flow characteristics : In the graph below shows the plot between flow and pulse in different settings and modes of working. The graph is nearly linear.

Output pulse sequence-In valve close state 1→2→3→4→5→6→7→8→1-In valve open state 8→7→6→5→4→3→2→1→8

1. If the LEV open angle is not change, all of the output phase will be OFF.2. If the output phase is different or continuously in the ON state, motor will not start smoothly and start

vibrating

Pulse signal output value and valve operation

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Issue No. :- TC-77040725Dated :- 8th July, 2004 TECHNICAL BULLETIN

-20

-15

-10

-5

0

5

10

15

20

0 100 200 300 400 500 600 700 800 900

Time(sec)

Supe

rhea

t(℃)

Starting Control

Regular Control

TargetSuperheat

Comparison : Below is the comparison between EEV and TXV.

Flow control : Super heat characteristic control

Control flow by microprocessor

Very high

Best

Best

Best

Best

EEV (LEV)

Control flow by DiaphragmWorking method

HighCost

NormalMultiple unit attachment

GoodSystem efficiency

BestDevice Reliability

GoodSystem Performance

TXV

☞ General working is show superheat values may be different for different refrigerants and models.