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Jockey Pump Operation - Staging Details
With the start of Drive 1 which is the Jockey Pump Lead (+) drive, the speed ramps up because of the low feedback.
If the feedback pressure had increased above the setpoint (not shown), Drive 1 would decelerate to a stop and
other motors would not run. Since the pressure did not build up, Drive 2 starts based on the three staging conditions
(feedback below setpoint, frequency of Drive 1 reaches staging frequency and the delay time has expired). Drive 2
(M2) starts
and now becomes the Main PI controlled drive. Drive 1 (M1) becomes a Lag (Aux) drive and runs
at the Fixed Lag frequency. There is a shift of the Main PI controlled drive from Drive 1 to 2.
After the Jockey
pump delay time AP1-89 (Jockey Dly T) has expired, Drive 1 (Jockey) will stop. If feedback still remains below the
setpoint, Drive 3 (M3) will start and
now Drive 3 becomes the Main PI controlled drive.
There is a shift of the
Main drive from Drive 2 to 3. Drive 2 becomes a Lag (Aux) drive
and runs at the Fixed Lag frequency. Drive 3
is operating with PI control as the Main drive.
Jockey Pump Operation - De-staging Details
Drive 1 (Jockey) had stopped after Drive 2 started and after the Jockey delay time. With two drives/motors/pumps
running, Drive 3 is the Main PI controlled drive. The feedback has increased to a level above the setpoint. When
the three conditions for de-staging Lag drives are met (feedback above setpoint, frequency reaches de-staging
frequency and the delay time has expired), Drive 3 (Main) decelerates and eventually stops. With FILO operation,
Drive 3 (M3) is the first to stop. Since Drive 3 (M3) is the Main PI controlled drive, a shift occurs making Drive 2 (M2)
the Main drive. As feedback continues to be above the setpoint, de-staging continues and Drive 2 (M2) decelerates
and stops. This is the
Last Out
for the FILO setting as Drive 1 (Jockey) had previously stopped.
Other Jockey Pump Operating Conditions
⚫
Only the Lead (+) drive can be set as Jockey pump.
⚫
When the Lead (+) drive is set as Jockey pump, all Lag drives are automatically set to Network Fbk.
⚫
When the Lead (+) drive is set as Jockey pump, the run priority AP1-43 (Run Priority) is fixed to the Drive’s
ID COM-01 (Int485 St ID) and cannot be changed. The run priority of the Jockey Pump drive is always
first.
⚫
The run priority of the rest of the drives follow the setting of the alternating sequence AP1-49 (ALT
Sequence).
⚫
When power is removed from the Jockey Pump drive, the system stops.
⚫
Alternation does not apply to the Jockey pump drive.
Summary of Contents for RSi H2P Series
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