Prevention Of Simultaneous Startup; Reverse Prevention Control - Hitachi SAMURAI Series Service Manual
Condenserless water chillers
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Also See for SAMURAI Series:
- Service manual (174 pages) ,
- Service manual (140 pages) ,
- Manual (118 pages)
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2. Control Functions
Control functions on the module
2.1.5 Prevention of simultaneous startup
This function prevents simultaneous startup when supplying power to multiple units (in case that all modules are working
individually, not in a master-slave group)
In case that multiple chiller units are installed, it may be thought that all of them will start operation simultaneously when
3 minutes have passed after entering in recovery from power interruption. (Note: When using the function to control
the number of units, simultaneous startup is prevented by performing sequential startup automatically. ) To prevent this
phenomenon, it is possible to shift the settings of time guard (3 minutes).
Setting method
By means of DIP switch setting (DSW3-1#, 3-2# ,3-3#), the following number of seconds are added to the time guard (3
minutes).
DIP switches (DSW3-1#, 3-2#, 3-3#) are used for address setting when using the functions to control the number of
units, but the addition of time to the 3-minutes guard is effective even if these functions are not used. In this case, it is not
necessary to connect transmission cables between each chiller unit. )
DSW3 (PCB
Unit No.
#1
#2
1
OFF
OFF
2
OFF
OFF
3
OFF
ON
4
OFF
ON
5
ON
OFF
6
ON
OFF
7
ON
ON
8
ON
ON
2.1.6 Reverse prevention control
The state of three-phase input is detected in this chiller unit, and it does not operate in case of reverse or open phase.
Three-phase input
detection
16
SMGB0097 rev.0 - 07/2015
)
Added
A
time
#3
#4
OFF
OFF
0 s
ON
OFF
5 s
OFF
OFF
10 s
ON
OFF
15 s
OFF
OFF
20 s
ON
OFF
25 s
OFF
OFF
30 s
ON
OFF
35 s
Reverse
phase
(Open R phase)
Open phase
(Open S phase)
(Open T phase)
Example: When setting 2 chiller units as unit 1 and unit 2,
upon recovery from momentary power interruption unit 1
restarts after 3 minutes and unit 2 restarts after 3 minutes
and 5 seconds.
N O T E
Power reactivation needed
Alarm display "Reverse/open phase"
Alarm display "Reverse/open phase"
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