6
Motor Protection
OVERCURRENT PROTECTION — CUSTOMER SUPPLIED
06CC 50-99 cfm compressors are supplied from the factory
without motor overcurrent protection devices. Fixed speed 06CC
compressors must be applied with properly sized overload relays
or calibrated circuit breakers to protect the motor against overcur-
rent fault conditions. These devices will protect the compressor
against running overcurrent, locked rotor, and primary and sec-
ondary single phasing. See 574-066 06CC Application Guide for
compressor electrical data and overload trip setting requirements.
Some fixed speed 06CC 50-99 cfm models may be configured
with a part winding start to reduce inrush current at startup.
Carlyle recommends a 1.0 to 1.25 second time delay between en-
ergizing the first and second windings.
Variable speed 06CC compressors may use the overcurrent pro-
tection features of the variable speed drive, providing that the
drive is listed with UL for this purpose. The overcurrent setting of
the drive must be consistent with the MCC (maximum continuous
current) value as defined in the 574-066 06CC Application Guide.
Overcurrent protection for all 06CC 50-99 cfm compressors must
be of the type that is manually reset. Overcurrent protection devic-
es that are automatically reset are not permitted.
Thermal Protection
All 06CC compressors are supplied with a discharge temperature
sensor located in the cylinder head of the compressor. (See Fig. 1)
This sensor is designed to open at 295°F, ±5°F (146°C, ±2.77°C)
and to close at 235°F (112°C). The discharge temperature sensor
operates as an automatic reset device; however, Carlyle recom-
mends that it is wired into the control scheme in a manner that al-
lows it to function as a manual reset device. The sensor will open
on temperature rise and close on temperature fall. The thermostat
pilot duty contacts are rated for a 125 sealed va and for an inrush
of 1250 va.
LUBRICATION SYSTEM
Oil Pressure Access Tee
1. For compressors without factory-installed electronic oil pres-
sure protection, the oil pressure access tee is supplied in a
separate parts bag with the compressor and is to be installed
in the oil pump above the oil pump cover.
2. Attach the high-side connection of an electro-mechanical oil
pressure safety switch to the opened flared end of the
installed oil pressure access tee. Refer to Fig. 1. The capped
end of this tee contains a Schrader-type valve, which permits
access to the oil pressure while the compressor is operating.
Oil Pressure Safety Switch
Differential oil pressure (oil minus interstage pressure) is
important to good compressor reliability. Carlyle recommends a
120 second time delay in the oil safety switch. The oil safety
switch protects the compressor when lubrication is lost for more
than 120 seconds. The switch closes the control circuit at startup,
allowing the compressor to run for 120 seconds. Operating oil
pressure must reach the minimum required start pressure above in-
terstage pressure within 120 seconds for the switch to remain
closed, which allows the compressor to run. If the operating oil
pressure falls below the minimum stop pressure above suction for
longer than 120 seconds, the switch will open the control circuit,
shutting down the compressor. Oil pressure protection devices
must be manual reset type.
Use of oil pressure protection is required for all fixed and variable
speed 06CC compressor applications, single and parallel compres-
sors. Table 4 shows electro-mechanical oil pressure differential
switches. See Fig. 1 for pressure connection locations.
The 06CC compressors are available with factory-installed oil
pressure protection. See Fig. 1. This factory-installed sensor elimi-
nates the need for any field piping connections. The electronic
portion of this oil pressure protection is available as a separate ac-
cessory for integrating into the system controls. Table 5 shows the
oil pressure differential electronic switch required to integrate the
factory-installed sensor into the system controls. Compressors
may be converted from electro-mechanical to electronic oil pro-
tection using Carlyle part number 06DA660115, which has the
same characteristics as shown in Table 5.
WARNING
Systems with VFD bypass contactors must include appropriate
overcurrent protection when operating in bypass mode.
CAUTION
Bearing Head is an aluminum material. Torque oil pressure
access tee to 20-25 lb-ft (27-33 Nm).
Table 4 — Electro-Mechanical Oil Pressure Protection
CARLYLE
PART NO.
TIME
DELAY
PRESSURE
CONNECTIONS
PRESSURE
DIFFERENTIAL SETTING
VOLTS
RESET
TYPE
REMOTE ALARM
CIRCUIT OPTION
CUT OUT CUT OUT
060B210991 120 sec 1/4 in. Male Flare
4-8 psid
(0.28-0.55 bar)
8-11 psid
(0.55-0.76 bar)
115/230-v Manual Yes
Table 5 — Electronic Oil Pressure Protection
CARLYLE
PART NO.
TIME
DELAY
USAGE
PRESSURE
DIFFERENTIAL SETTING
VOLTS
RESET
TYPE
REMOTE ALARM
CIRCUIT OPTION
CUT OUT CUT OUT
06DA509570
120 sec
Electronic Switch for
Factory-Installed Sensor
4-8 psid
(0.28-0.55 bar)
8-11 psid
(0.55-0.76 bar)
115/230-v Manual Yes
06DA660115 Field Conversion Kit
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