Data Sheet

Panasonic Corporation Electromechanical Control Business Division
industrial.panasonic.com/ac/e/
Cautions for Use of Solid State Relays
Panasonic Corporation 2020
Snubber Circuit
Reduce dv/dt
An SSR used with an inductive load can accidentally re due to a
high load voltage rise rate (dv/dt), even though the load voltage is
below the allowable level (inductive load ring).
Our SSRs contain a snubber circuit designed to reduce dv/dt (except
AQ-H).
Selecting the snubber constants
1) C selection
The charging coe󰀩cient tau for C of the SSR circuit is shown in
formula
①
τ
=(R
L
+R) × C ------------
①
By setting formula
①
so that it is below dv/dt value you have:
C=0.632V
A
/[(dv/dt) (R
L
+R)] -----
②
By setting C = 0.1 to 0.2 μF, dv/dt can be controlled to between
nV/μs and n+V/μs or lower. For the condenser, use either an MP
condenser metallized polyester lm. For the 100 V line, use a
voltage between 250 and 400 V, and for the 200 V line, use a
voltage between 400 and 600 V.
2) R selection
Load power supply
Inductive load
Snubber circuit
SSR
1
VA
RL
R
C
2
If there is no resistance R (the resistance R controls the discharge
current from condenser C), at turn-on of the SSR, there will be a
sharp rise in dv/dt and the high peak value discharge current will
begin to ow.
This may cause damage to the internal elements of the SSR.
Therefore, it is always necessary to insert a resistance R. In
normal applications, for the 100 V line, have R = 10 to 100 Ω and
for the 200 V line, have R = 20 to 100 Ω. (The allowable discharge
current at turn on will di󰀨er depending on the internal elements of
the SSR.) The power loss from R, written as P, caused by the
discharge current and charging current from C, is shown in
formula
③
below. For the 100 V line, use a power of 1/2 W, and
for the 200 V line, use a power above 2 W.
P
＝
C
×
V
A
2
×
f
2
………③
f
＝
Power supply frequency
Also, at turn-o󰀨 of the SSR, a ringing circuit is formed with the
capacitor C and the circuit inductance L, and a spike voltage is
generated at both terminals of the SSR. The resistance R serves
as a control resistance to prevent this ringing. Moreover, a good
non-inductive resistance for R is required. Carbon lm resistors or
metal lm resistors are often used.
For general applications, the recommended values are C = 0.1
μF and R = 20 to 100 Ω. There are cases of resonance in the
inductive load, so the appropriate care must be taken when
making your selections.
Thermal Design
SSRs used in high-reliability equipment require careful thermal design.
In particular, junction temperature control has a signicant e󰀨ect on
device function and life time. The rated load current for PC board-
mounting SSRs is dened as the maximum current allowable at an
ambient temperature of 40 °C (30 °C) and under natural cooling. If the
ambient temperature exceeds the SSRs derating temperature point [40
°C (30 °C)], load current derating in accordance with the load current
vs temperature diagram becomes necessary. If adjacent devices act
as heat sources, the SSR should be located more than 10 mm away
from those devices.
SSRs with a 5 A rating or more must be used with the dedicated heat
sinks listed in Table 1 or equivalents. To ensure adequate thermal
conduction, apply thermal conductive compound (Ex. Momentive
Performance Materials Inc. YG6111 or TSK5303) to the SSR’s
mounting surface. For information on external heat sinks for our SSRs
and their mounting method, refer to “Data and Cautions for Use for
respective relay”.
Table 1 Dedicated on-board heat sinks
Type Heat sink Load current
AQ 10 A 2 -ZT 4 / 32 VDC AQ 1802 10 A
AQ-J (
10 A)
AQP 810 *
10 A
AQP 813
AQP 812 *
AQ-J ( 15 A)
AQP 810 *
15 A
AQP 813
AQP 812 *
AQ-J ( 25 A)
AQP 810 *
20 AAQP 813
AQP 812 *
AQP
815 25 A
AQ-A (
15 A)
AQP 813
15 A
AQP 812 *
AQ-A ( 25 A)
AQP 814
25 AAQP 813
AQP 812 *
AQ-A ( 40 A)
AQP 813
30 A
AQP 812 *
AQP
814
40 A
AQP 815
AQ-A DC ( 10 A)
AQP 812 *
8 A
AQP 815 10 A
AQ-A DC (
30 A) AQP 812 * 30 A
* It is possible to mounting on the DIN rail
ASCTB400E 202003
ー 13 ー