SE-K2EN Omron, SE-K2EN Datasheet - Page 12

• Manufacturer Part Number: SE-K2EN
• Description: RELAY MOTOR PROTECT 200/220/240V
• Manufacturer: Omron
• Series: SEr

Specifications of SE-K2EN

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: SEK2EN

Q
Q
Q
Q
Q
When using the SE as a 2E (overload and open-phase)
relay, can the control power supply voltage be supplied
separately from the motor circuit?
Yes. Operation will be correct.
What is the input volt-amp consumption of the SET-3@?
Input Volt-Amp Consumption of SET-3@ at Rated Current
Why is the control power supply 100/110 V?
The main reason the SE uses a 100/110-V control power
supply is because 100/110 V is applicable to high-voltage
motor protection. With a high-voltage motor, the voltage is
first reduced with a potential transformer, and the secondary
side is connected to the SE. When using the SE as a 2E
(overload and open-phase) relay, a normal 100-V power
supply can be used without connecting to the secondary side
of a potential transformer.
How long of a power interruption is required to restart
the startup lock timer with an Instantaneous-type SE
Relay (with startup lock)?
Approx. 0.5 s min.
Why is it not possible to use the SE in a circuit
containing thyristor control or a rectifier?
A schematic diagram showing the operating principle for the
SE is shown below.
As shown in the above diagram, the waves for all three
phases of the motor current from the CT of the SET-3@ are
rectified, then converted to DC voltage, which is necessary
for the SE, by the resistor at each tap, and output from the
positive and negative terminals. The DC and AC component
ratios in this voltage differ between the normal three-phase
condition and conditions of phase-failure or unbalance.
SET-3A
SET-3B
M
Questions and Answers
CT
At 20 A for 20-A model
At 40 A for 40-A model
At 80 A for 80-A model
At 160 A
20
40
80
SET-3@
Approx. 0.1 VA/phase
Approx. 0.2 VA/phase
Approx. 0.4 VA/phase
Approx. 0.4 VA/phase
(+)
(−)
(7)
(8)
SE
For the overload factor, the DC average level is detected relative to
the set value. For the phase-failure factor, the proportion of the DC
average level and AC component is used to distinguish phase failure
or unbalance.
When the motor is operated using thyristor phase control, the motor
current waveform is not a sine wave. The SE detects this as an
adverse condition and initiates unnecessary operations. The
example below shows a primary current and SET-3@ output
waveform. When there is a large AC component in the output
voltage, the SE series sometimes judges it to be a phase-failure and
initiates unnecessary operations.
Normal three-phase condition Complete open-phase loss
Unbalance
3.54 A
0
0
5 V
3.54 A
76°
5 V
11°
10 ms
Output voltage
• Load current: 2.50 A (actual value)
• SET-3A output voltage: 21.77 VDC
• Phase control accuracy: 11°
10 ms
Output voltage
Current
Current
• Load current: 2.50 A (actual value)
• SET-3A output voltage: 21.00 VDC
• Phase control accuracy: 76°
DC
average
Value
SE
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