GE Industrial Solutions DV-300 DC Drive Users Manual - Manual (Page 179)

DV-300 Adjustable Speed Drives
——— FUNCTION DESCRIPTION ———
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Enable fbk bypas Enable of the automatic change into an armature feedback when the failure message
“Speed fbk loss” is caused by a lack of the encoder or tachometer feedback.
Enabled Enabled automatic change
Disabled Disabled automatic change
After an automatic change into an armature feedback, the speed regulator works with the
Speed P bypass and Speed I bypass parameters of the REG PARAMETERS/Percent
values/Speed regulator menu. The failure message “Speed fbk loss” with an enable must
be configured so that it is set as “Activity = Warning”.
Possible working only with constant field current.
Flux weak speed Speed value as a percentage of Motor max speed, when the Voltage control phase starts.
The Flux weak speed parameter, when the speed feedback control is enabled (Enable
fbk contr = Enabled), is used to underline the fact that during the Voltage control phase
the armature voltage and the feedback signal are not proportional. If the drive works
with a constant torque on the whole regulation range (Flux reg mode = Constant Cur-
rent), it is necessary to insert the factory set 100% value.
Speed fbk error Max. allowed error expressed as a percentage of the max. output voltage (Max out
voltage). By means of Max out Voltage, Flux weak speed and Motor nominal speed a
relation between motor speed and armature voltage is obtained. If a difference higher
than Speed fbk error occurs a Speed fbk loss failure occours.
Tacho scale Fine scaling of the speed feedback using a tachometer analog generator (Speed fbk sel
= Tacho). It is a multiplier of the read tach voltage.
For example:
Analog tach = 60V/1000 rpm, motor top running speed 3000 rpm.
Maximum tach volts = (60V/1000 rpm*3000rpm)= 180 VDC.
- Set dip-switch S4 for 181.6V (see table 4.4.3)
- Set the tacho scale parameter = 181.6V / 180V = 1.01
- Fine adjust the value of Tacho scale if the 180 VDC tach voltage is not perfectly reached.
Speed offset Offset scaling of the feedback circuit.
Encoder 1 pulses Number of pulses per revolution of the sinusoidal encoder connected to the XE1 connector.
Encoder 2 pulses Number of pulses per revolution of the digital encoder connected to the XE2 connector.
The Encoder 2 pulses and Motor max speed shall be inside the allowed area shown
in figure 6.11.4.2
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Motor max speed vs PPR
Motor
max
speed
Encoder 2 pulses
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Figure 6.11.4.2: Allowed area for Encoder 2 pulses and Motor max speed
Refresh enc 1 Enable the monitoring of the encoder 1(connector XE1) connection status, in order to