York YCAS Series, Installation Operation & Maintenance

Page: 16 / 216

16 YORK INTERNATIONAL
FORM 201.19-NM8 (804)
The micro also provides low motor current protection
when it senses a motor current less than 10% FLA. The
micro will shut the system down whenever low motor
current is sensed and will lock out a system if three faults
occur in 90 minutes. Low motor current pro tec tion is ac-
tivated 4 seconds after start on both Wye-Delta and ACL
starters to assure the motor starts, the sys tem doesn’t run
with out refrigerant, the motor protector is not tripped,
and the mechanical high pres sure cut-out is not tripped.
Once the system is locked out on Low Motor Current,
it must be manually reset with the sys tem switch. See
also Motor Protection Module section below.
The micro senses low motor current whenever a HPCO
or Motor Protector contact opens. This occurs because
the MP and HPCO contacts are in series with the mo tor
contactor. Whenever either of these devices are open,
the contactor de-energizes and the motor shuts down.
Since the micro is sending a run signal to the contactor,
it senses the low motor current below 10% FLA and
shuts the system down.
Motor Protection Modules (2ACE)
The mechanical motor protector is a Texas In stru ments
2ACE Three Phase Protection Module (Fig. 73) pro-
vides thermal and cur rent motor overload pro tec tion.
This mod ule also pro tects against phase to phase cur-
rent im bal ance, over cur rent, under current, and phase
ro ta tion. The mod ules, mount ed in the power pan els,
uti liz es a 7 seg ment display which provides op er at ing
sta tus and fault di ag nos tic in for ma tion. The 7 segment
dis play will dis play ei ther a sta tion ary or a fl ash ing al-
pha nu mer ic value which can be de cod ed by the op er a tor.
A list of the codes is shown in the table below.
Whenever a motor protector trips, the motor pro tec tor
contacts wired in series with the motor contacts opens
and the motor contactor de-energizes causing the mo-
tor to stop. The micro senses the low motor current
and shuts the system down. The micro will try two
more starts be fore locking the system out. The system
locks out be cause the motor protector is a man u al re-
set de vice. Af ter the fi rst start, the modules’ contacts
will be open pre vent ing the motor contactors from
en er giz ing. Power must be removed and re applied to
re set the mod ule.
Current Overload
The 2ACE module design uses one integral current
trans form er per phase to provide protection against
rap id current over load conditions. The module re sponds
to changes in current and must be cal i brat ed using DIP
switches lo cat ed on the module. Integral trip curves al-
low for in-rush cur rents dur ing Wye-Delta, part wind,
or ACL starts with out nuisance tripping.
To check the factory setting of the 2ACE module cur rent
overload trip value. See Table 1 (pages 18 and 19).
For the location of the dip switches and determining
the OPEN side of the switches, refer to Fig ure 73. As
in di cat ed, to place a switch in the ON po si tion re quires
push ing the switch to the left.
A switch must be pushed to the
left to place the switch in the ON
position. The numerical valve for
the combination of "ON" switches
equals the overload setting.
It is recommended that a YORK
Ser vice Tech ni cian or the YORK
fac to ry be con sult ed before chang ing
these settings for any rea son, since
dam age to the com pres sor could
re sult. Chang es should nev er be
made un less it is ver i fi ed that the
set tings are in cor rect.
Product Description
HAXXX
Normal motor OFF display. Sequentially
sweeps through the motor protection dip
switch setting.
0
Normal - no fault detected (Running)
Flashing “0”
Motor off or un load ed < 5A (Running)
AC current lev el.
1
High cur rent fault.
2
Loaded phase to phase cur rent
imbalance > 17%.
3
Unloaded phase to phase cur rent
imbalance > 25%.
4
Improper in com ing phase ro ta tion.
5
High motor tem per a ture. Trip point =
13kW, re set = 3.25kW.
6
Communication error.
7
Unload imbalance ( > 50%)
8
Phase Loss (> 60%)
E
Out of range of RLA cal i bra tion.
Other symbols
Defective module or supply volt age.
Working voltage 18 - 30 VAC, 24 VAC nominal.
Low volt age trip
= 15 VAC.