Crompton Controls M20 - Manual (Page 6)

Emotron AB 01-2551-01r4 Description 5
3 Description
This instruction manual describes the installation and commissioning of the
Emotron M20 shaft power monitor. The Emotron M20 supervises induction
motor driven equipment and provides warnings when abnormal conditions are
detected. It protects for example, pumps and other equipment. The M20’s abil-
ity to provide reliable monitoring and protection ensures that production equip-
ment is optimized and expensive breakdowns and interruptions are minimized.
The Emotron M20 uses the motor as its own sensor and no external sensors or
extra cabling are required. Due to the special method of subtracting motor
power losses, the monitor is able to accurately measure the shaft power supplied
by the motor to the application. This advanced technique allows the M20 to
monitor only the “application” load rather than the “total” motor load, which
includes the varying motor losses.
The shaft power is calculated by measuring motor input power, and subtracting
the motor power loss calculated using a unique principle. The shaft power out-
put is indicated on the monitor display in kW or HP, or as a percentage of rated
power. Calculating shaft power gives more reliable supervision than non-linear
techniques, such as current and phase angle measurements. Current measure-
ment is only sufficient at high motor loads and phase angle only at low loads.
Input power is sometimes called true or real power. Input power is linear, but
ignores motor power loss.
The M20’s analogue output and two relay outputs allow the combination of
direct and indirect control. The unit offers high accuracy in the event of very
small load variations. The analogue output signal can be used to scale the
machine load to represent the actual working range.
The monitor is very easy to install and set up and should be mounted on a
standard DIN rail. It is also very easy to use. The “Auto set” function makes it
possible to adjust the monitor automatically by pressing just one key.
The M20 provides complete flexibility in terms of the type of protection
required for your application. You may select either overload and underload
protection or simply overload with pre-alarm or underload with pre-alarm.
Independent response delays can be selected for both overload and underload
protection. Additional flexibility is provided in the form of programmable out-
put relays, number of start attempts, number of reversing attempts etc.