Carlyle 05T-048 애플리케이션 매뉴얼 - 페이지 8

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2.6 Mechanical Unloading

All Carlyle screw compressors are equipped with one step

of mechanical unloading. The unloader valve is controlled

by a solenoid mounted on the compressor body. The com-

pressor is unloaded when the solenoid is de-energized

and loaded when the solenoid is energized. The compres-

sor should always be started unloaded (for a minimum time

determined by the control module) which will provide a soft

start by partially relieving the compression chamber back to

suction. Unloaded operation reduces the effective capacity

by 30% to 62%, depending on the model and system condi-

tion (see tables below).

ESTIMATED PERCENTAGE UNLOADING

BY MODEL

50HZ OPERATION

COMPRESSOR

06TR

MODEL

MODELS

06T—033

62%

06T—039

61%

06T—044

60%

06T—048

59%

06T—054

58%

06T—065

55%

06T—078

50%

06T—088

47%

06T—108

45%

Capacity

Control

The 05T/06T screw compressors can be run unloaded con-

tinually without affecting the reliability of the compressor.

2.7

High Discharge Pressure Control

A high pressure cut out must protect the compressor from

exceeding 350 psig (25.2 bar). The compressor may be

brought back online after the discharge pressure falls below

300 psig (21.4 bar). The maximum pressure differential

60HZ OPERATION

06TA

06TR

06TA

MODELS

52%

60%

51%

59%

50%

58%

49%

56%

48%

55%

45%

50%

40%

45%

37%

40%

—

Vi Control

(05/06TR only)

(discharge-suction) is 350 psi. The internal pressure relief

valve will open if the pressure differential exceeds 400 psi

(+/-3%).

2.8 Low Suction Pressure Cut Out

A low suction pressure cut out must protect the compressor

from operating below 10 inches of vacuum pressure. Each

compressor must be individually protected with a low pres-

sure switch connected to the low side access port. The

compressor may be brought back online after a 3 minute

delay.

2.9 Volume Index (Vi) Control

All low temperature models (05TR/06TR) are supplied with

a Vi control valve that allows for two Vi settings (see chart

below). This dual Vi allows for optimum efficiency over a

wide range of head pressures. The Vi must be set to low

(solenoid de-energized) during start-up for a minimum of 30

seconds. The Vi may then be set as desired for optimum en-

ergy efficiency. The following table reflects the operational

50%

recommendations for the Vi control. Carlyle also recom-

49%

mends the use of a small deadband at this change-over

48%

point to avoid unnecessary short cycling of the Vi solenoid.

46%

The LonCEM

45%

ing pressure ratio and controls Vi output accordingly. The

40%

older CEM requires external controls to accomplish the

35%

same task.

30%

Compressor

—

Model

06TR

06TA

2.10 Reverse Rotation Protection

Correct compressor rotation is critical for compressor reli-

ability. The compressor can fail within 2 seconds of start-up

if it is not rotating in the correct direction. Installation of a

pressure gage at the discharge pressure access fitting in

the compressor body (measuring the pressure upstream of

the integral discharge check valve) is recommended during

initial start-up or whenever the compressor is serviced. The

gage should be monitored to ensure increasing discharge

pressure at start-up.

The LonCEM protection module uses a pressure sensor to

monitor the discharge pressure change at startup to ensure

proper compressor rotation. The LonCEM module elimi-

nates the need for a mechanical low-pressure switch and

line/load phase monitor. See Appendix A for descriptions of

operation applications for the LonCEM module.

2.11 Mufflers

Screw compressors emit gas pulsations result in radiated

noise from the discharge line and oil separator. The addition

of a muffler is required in all applications to reduce dis-

charge line and oil separator noise levels. The muffler

should be located within 6-inches (15cm) of the compressor

discharge service valve.

controller continuously monitors the operat-

System

Pressure Ratio

setting

>5.0

High:4.0

<5.0

Low: 2.8 De-energized

Fixed:

All

2.8

Solenoid

State

Energized

—