ZENAMIC
METAL OXIDE VARISTOR
ZENAMIC is the product name of a metal
oxide varistor.
ZENAMIC Transient/Surge Absorber, Series
D is newly released through our continued
research in ceramic material composition of
ZnO varistor and manufacturing process,
featuring large surge current handling
capability and energy handling capability
for absorbing transient overvoltage in
compact size.
.A=JKHAI
Improved in "Surge Current Handling
Capability (at 8/20 s, 2 times)" by about 2
times over the current.
Very large "Energy Handling Capability"
absorbing transient overvoltages in
compact sizes.
Lower Clamping Voltage for better surge
protection.
Fast response to high speed transient/
surge voltage.
Wide products range for transient/surge
protection on AC 100V to AC 480V
nominal system with the maximum peak
current ratings of 600A to 7000A (at 8/20
s, 2 times).
31
ZENAMIC has the forward-reverse symmetrical
electrical characteristics as shown in the figure 1.
The voltage-current curves show the varistor
characteristics in the range 1 A to 10
4
A, and show
the resistance characteristics for the range under
1 A and over 10
4
A in the figure 2.
The voltage across terminals when test current(It:
1 mA)is applied to ZENAMIC is the standard varistor
voltage(Vz), and the voltage across terminals when
a standard surge(Ip) is applied represents the
maximum suppression voltage(Vc).
V- characteristics
A surge waveform varies according to the sources.
An EXP waveform is used for surge testing of
ZENAMIC, while a AC half-wave is used for the
energy absorption test. The EXP waveform reaches
its peak voltage (current) at [ta] as shown in the
figure 5, and then decreases as time passes and
reaches half of the peak voltage (current) at [tb].
This type of the EXP waveform is shown as a [ta/tb]
voltage (current) waveform. For surge testing
of ZENAMIC, the 8/20 sec current waveform is
used.
Surge waveform
3) In case that ZENAMIC is used in line to ground, the
ground fault circuit interrupter should be applied in
location A or thermally coupled fuse should be applied
in location C.
Part Number
Rating of fuse
Z7D
5A max.
Z10D
7A max.
Z15D
Z21D
Part Number
Rating of fuse
15A max.
10A max.
Refer to the related Safety Standards.
Power lines and surge absorption units with error
display (SA series).
Voltage(V)
Current (%)
400
200
0
200
400
5
4
3
2
1
0
1
2
3
4
5
Current (A)
10
0
ta
tb
2,000
1,000
Voltage(V)
500
200 Varistor voltage
R
p
100
50
20
10
I
E
C
Test current
Clamping voltage
Surge current
R
s
Time( s)
100
90
Applications
Line to line protection
50
DC
AC single phase
f
Protected
circuit
Fig 1
f
AC three phase
f
f
Protected
circuit
Fig 5
Part Number.
Line to line and line to ground protection
DC
AC single phase
f
Protected
circuit
Thermal
coupling
Z 10 D 221
Fig 2
5
10 9 8 7
10 10 10 10 10
6
10
5
10
4
10
3
10
2
10
1
10
0
10
1
10
2
10
3
10
4
Current (A)
Taping code
T4C : Clinch lead taping
T4D : Straight lead taping
Varistor voltage
D series
Element diameter
ZENAMIC symbol
f
In the small current range, ZENAMIC features
outstanding temperature characteristics. A shunt
resistance Rp of metal oxide varistor has the
temperature characteristics which is determined by
the following equation.
Rp AeEg/2kT
(2)
T:Absolute temperature
k:Boltzmann constant
A, Eg:constants
500
400
300
200
100
50
40
30
20
10
10
10
Temperature characteristics
f
AC three phase
f
f
Protected
circuit
Thermal
coupling
f
25 C
60 C 90 C 120 C
Test current
1.A surge excess of the specified Maximum Peak
Current may cause short circuit or mechanical
damage. The following measures are recommended.
In case that ZENAMIC is used in line to ground, the
ground fault circuit interrupter shall be applied in
location A or thermally coupled fuse shall be
applied in location C.
ZENAMIC shall not be used near heat generating
device and free from direct sunlight.
ZENAMIC shall not be used near the flammable
materials.
A
Power line
B
Protected
circuit
Application notes(General)
Switching surge
protection
Semiconductor
protection
Contact spark
suppression
Voltage(V)
M
Motor
10
9
10
8
10
7
10
6
10
5
10
4
Fig 3
10
3
10
2
Current (A)
10
1
Single line and telephone line surge protection
Surge protection of
signal Line
Protected
Equipment
As shown in the figure 3, the temperature dependence
characteristics are shown clearly in the low current area.
COM
.
C
1)Location of the over current protector(circuit breaker
or current fuse)shall be in the power line to the
circuit(Location A)or in series with ZENAMIC
(Location B).
2) It recommended that a fuse listed in the table be put
in location A or B.
32
Surge protection of
telephone Line
Telephone
Talking
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