33
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 104A, and show
the resistance characteristics for the range under
1 A and over 104A 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).
Z 10 D 221
Varistor voltage
D series
Element diameter
ZENAMIC symbol
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
Power lines and surge absorption units with error
display (SA series).
Applications
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.
Temperature characteristics
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.
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.
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.
Application notes(General)
Part No.
0
200
200
400
400
012345
1
2
3
4
5
Current (A)
Time( s)
Fig 1
Fig 5
5
10
20
50
200
500
100
2,000
1,000
10
10
9
10
8
10
7
10
6
10
5
10
4
10
3
10
2
10
1
10
0
10
1
10
2
10
3
10
4
10
Current (A)
Fig 2
Clamping voltage
Varistor voltage
Rp
Rs
Test current
Surge current
I
C
E
10
20
50
40
30
200
500
400
300
100
10
10
9
10
8
10
7
10
6
10
5
10
4
10
3
10
2
10
1
10
Current (A)
Fig 3
100
90
50
10
0
ta
tb
Rp AeEg / 2kT
T:Absolute temperature
k : Boltzmann constant
A, Eg:constants
As shown in the figure 3, the temperature dependence
characteristics are shown clearly in the low current area.
(2)
Test current
25 C60 C90 C 120 C
Protected
Equipment
COM
.
Surge protection of
signal Line
Surge protection of
telephone Line
Telephone
Protected
circuit
Power line
A
B
C
Protected
circuit
Part Number
Rating of fuse
3A max.
5A max.
7A max.
Part Number
Rating of fuse
Refer to the related Safety Standards.
10A max.
15A max.
Line to line protection
Line to line and line to ground protection
Single line and telephone line surge protection
DC
AC single phase
AC three phase
Protected
circuit
f
Protected
circuit
DC
AC single phase
Switching surge
protection
Semiconductor
protection
Contact spark
suppression
f
f
f
f
f
AC three phase
Protected
circuit
f
f
f
f
Thermal
coupling
Thermal
coupling
M
Motor
Z5D
Z7D
Z10D
Z15D
Z21D
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