KEPCO KLN Series (750W, 1500W, 3000W), Main Contro Firmware Version 1.70 and higher - Manual (Page 34)

2-8 KLN Series 051614
all applicable electric codes for safety grounding requirements are met. As a precaution, always
connect the screw marked
at the rear panel to proper earth ground.
2.5.2 SOURCE POWER CONNECTIONS
Source power is connected to the power supply via three-wire input power using the source
power cable supplied (see Table 1-4). See Table 1-2 for source power specifications. This power
supply operates from single phase a-c mains power (or between two phases of 3-phase a-c
mains power) over the specified voltage and frequency ranges (Table 1-2) without any need for
range selection.
CAUTION: DO NOT USE AC SUPPLY WHICH EXCEEDS THE INPUT VOLTAGE AND FRE-
QUENCY RATING OF THIS INSTRUMENT. THE INPUT VOLTAGE AND FRE-
QUENCY RATING OF THE POWER SUPPLY ARE SHOWN IN TABLE 1-2. FOR
SAFETY REASONS, THE MAINS SUPPLY VOLTAGE FLUCTUATIONS MUST
NOT EXCEED ±10% OF NOMINAL VOLTAGE.
2.5.3 D-C OUTPUT GROUNDING
Connections between the power supply and the load and sensing connections may, despite all
precautions such as shielding, twisting of wire pairs, etc., be influenced by radiated noise, or
“noise pick-up”. To minimize the effects of this radiated noise the user should consider ground-
ing one side of the power supply/load circuit. The success of d-c grounding requires careful
analysis of each specific application, however, this recommendation can only serve as a general
guideline.
One of the most important considerations in establishing a successful grounding scheme is to
avoid GROUND LOOPS. Ground loops are created when two or more points are grounded at
different physical locations along the output circuit. Due to the interconnection impedance
between the separated grounding points, a difference voltage and resultant current flow is
superimposed on the load. The effect of this ground loop can be anything from an undesirable
increase in output noise to disruption of power supply and/or load operation. The only way to
avoid ground loops is to ensure that the entire output/load circuit is fully isolated from ground,
and only then establish a single point along the output/load circuit as the single-wire ground
point.
The exact location of the “best” d-c ground point is entirely dependent upon the specific applica-
tion, and its selection requires a combination of analysis, good judgement and some amount of
empirical testing. If there is a choice in selecting either the OUTPUT or COMMON output termi-
nals of the power supply for the d-c ground point, both sides should be tried, and preference
given to the ground point producing the least noise. For single, isolated loads the d-c ground
point is often best located directly at one of the output terminals of the power supply; when
remote error sensing is employed, d-c ground may be established at the point of sense lead
attachment. In the specific case of an internally-grounded load, the d-c ground point is automat-
ically established at the load.