CONTREX MLP-Drive - Manual (Page 60)

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Follower Mode Examples A and B
Example A demonstrates how scaling and setpoint Control Parameters are entered for
a typical Follower mode of operation that uses a ratio setpoint:
The Lead pump delivers 10 gallons/minute when the motor is running at
a maximum RPM of 1725. The Lead sensor shaft is equipped with a 60
tooth Ring kit. The Follower pump delivers 30 gallons/minute when the
motor is running at a maximum RPM of 1800. The Follower sensor
shaft is equipped with a 30 tooth Ring kit. Follower Setpoint 1 will be
set so that when the Lead pump delivers 5 gallons/minute, the Follower
pump will deliver 15 gallons/minute. Follower Setpoint 2 will be set so
that when the Lead pump delivers 5 gallons/minute, the Follower pump
will deliver 22.5 gallons/minute.
Table 3-17 shows the Control Parameters that would be entered in the MLP–Drive for
Example A.
To find the ratio for the Follower Engineering Units (CP-21) for Example A:
Follower E.U. at Max Follower RPM 30
Follower E.U. (CP-21) = _____________________________________________________ = ___ = 3
Lead E.U. at Max Lead RPM 10
30 gal / min The Follower Engineering Units when the Follower is operating
at the maximum RPM.
Divided by
10 gal / min The Lead Engineering Units when the Lead is
operating at maximum RPM.
Equals
3.00 Follower Engineering Units (CP-21) as a ratio of Follower to
Lead.