Emerson E2 Einstein Manual page 20

Control Techniques Drives Ltd.
TECHNICAL NOTIFICATION
Title: Commander SK Size 3 Earth Leakage Current
Product: Commander SK
N/A
Variant:
Category: General
Issued By: Dominic Sim
SUMMARY
It has been highlighted that not all users are following the advice given in the Commander SK
manuals, with respect to hazards of unrestricted access to the control circuits, if they are not
earthed/grounded.
Failure to comply with this advice may result in an electric shock.
MORE INFORMATION
There is a voltage present between 0V and ground/earth, which is due to capacitive coupling
between the power and control circuits in the inverter.
The stray capacitance between the power and control circuits results in a high frequency leakage
current flowing (when the drive is running). The current flow is dependant on the level of
capacitance present. Note that due to the high frequency content, it cannot be measured
accurately by a DVM.
The size 3 has a relatively high capacitance compared to size 2 and the current can cause a
painful shock, which is not directly hazardous, but could lead to an accident.
The leakage current present on the Commander SK size 3 can cause interference with the Serial
Communications on the drive, due the leakage current being present on the Serial
Communications 0V connection. Therefore contact with exposed communication cable
connections should be avoided.
Issue Date:
Date Codes:
Manuals affected:
Priority:
T080101
14-January-2008
Yes
Normal
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