1-6 Product Overview
1560D-UM051D-EN-P – February 2005
Protection and Diagnostics The MV Dialog Plus™ controller is capable of providing the following
protective and diagnostic features:
Overload
The MV Dialog Plus controller meets applicable requirements as a motor
overload protective device. Thermal memory provides added protection
and is maintained even when control power is removed. The built-in
overload algorithm controls the value stored in Parameter 11, Motor
Thermal Usage (see Chapter 4, Programming). An Overload Fault will
occur when this value reaches 100%. The programming parameters below
provide application flexibility and easy setup. See Note 3.
Parameter Range
Overload Class Off, 10, 15, 20, 30
Overload Reset Manual – Auto
Motor FLC 1.0 – 999.9 amps
Service Factor 0.01 – 1.99
Important: During slow speed and/or braking operations, current
waveforms exhibit non-sinusoidal characteristics. These non-sinusoidal
characteristics inhibit the controller's current-measurement capability.
To compensate for additional motor heating that may result, the controller
uses motor thermal modeling, which increments motor thermal usage.
This compensation takes place when these options are in use: Preset
Slow Speed, Smart Motor Braking, and Slow Speed with Braking.
Notes:
1. The factory default setting for Overload Class, which is "OFF", disables
overload protection. An overload trip class and the motor's full-load
current rating must be programmed to enable overload protection.
2. A Bulletin 825 converter module (Cat. No. 825MCM20) is required to
provide current feedback during bypass operation.
3. If the motor is started with the bypass contactor closed, the overload
function in the MV Dialog Plus is automatically disabled. In this case,
a separate overload relay is required.
4. Automatic reset of an overload fault requires the start input to be
cycled in a two-wire control scheme. This applies to the following
firmware releases: 1.07 (standard), 1A07L (Soft Stop), and 1B05L
(Pump Control) or earlier.
5. If the MV Dialog Plus is used to control a multi-speed motor, or more
than one motor, the Overload Class parameter must be programmed to
"OFF" and separate overload relays must be supplied for each speed/
motor.
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