Timers
Delay on Release
Types B 128, B 121
• Time ranges: 0.15 s to 60 s
• Automatic start after drop out of power supply
• Knob-adjustable time within range
• Repeatability deviation:
≤
1%
• Output: 10 A SPDT relay
• Plug-in type module
• Scantimer housing
• LED-indication for supply on
• AC or DC power supply
Product Description
Mono-function, plug-in, delay
on release, miniature time re-
lays up to 60 s covering 2
individual time ranges. These
economical timers are often
used to switch on an exhaust
fan and keep it running for a
certain period of time after
disconnection of power sup-
ply.
Ordering Key
Function
Output
Type
Power supply
Time range
B 128 220 006
Type Selection
Plug
Circular
8 pins
Circular
11 pins
Output
SPDT
SPDT
Time ranges
0.15 - 6 s
1.5 - 60 s
0.15 - 6 s
1.5 - 60 s
Supply: 24 VAC
B 128 024 006
B 128 024 060
B 121 024 006
B 121 024 060
Supply: 120 VAC
B 128 120 006
B 128 120 060
B 121 120 006
B 121 120 060
Supply: 220 VAC
B 128 220 006
B 128 220 060
B 121 220 006
B 121 220 060
Supply: 24 VDC
B 128 724 006
B 128 724 060
B 121 724 006
B 121 724 060
Time Specifications
Time ranges
Time range accuracy
0.15 -
6s
1.5 - 60 s
0 to +20% on max.
min. actual time
≤
min.
set time
≤
1%
≤
0.05%/V
≤
0.2%/°C
Power supply interruption
≥
500 ms
Output Specifications
Output
Basic electrical insulation
Contact ratings
(AgCdO)
Resistive loads
AC 1
DC 1
or
Small inductive loads AC 15
DC 13
Mechanical life
Electrical life
AC 1
SPDT relay
250 VAC (rms)
(contact/electronics)
µ (micro gap)
10 A/250VAC (2500 VA)
1 A/250 VDC (250 W)
10 A/25 VDC (250 W)
2.5 A/230 VAC
5 A/24 VDC
≥
30 x 10
6
operations
≥
2.5 x 10
5
operations
(at max. load)
≤
7200 operations/h
Repeatability deviation
Time variation
Within rated power supply
and ambient temperature
Reset
Time and/or relay
Operating frequency
Insulation voltages
Rated insulation voltage
≥
2.0 kVAC (rms) (cont./elec.)
Rated transient protection volt. 4 kV (1.2/50 µs) (cont./elec.)
(IEC 60664)
Specifications are subject to change without notice (25.10.99)
1
B 128, B 121
Supply Specifications
220 VAC ±15%,
45 to 65 Hz
120 VAC ±15%,
45 to 65 Hz
024
24 VAC ±15%,
45 to 65 Hz
Dropout tolerance
≥
10 ms
Rated insulation voltage
None
Rated transient protection volt. 4 kV (1.2/50 µs) @ 220 VAC
2.5 kV (1.2/50 µs) @ 120 VAC
800 V (1.2/50 µs) @ 24 VAC
(line/neutral)
Power supply DC type
Installation cat. III (IEC 60664)
Rated operational voltage 724 24 VDC + 15/- 20% (pin 2 pos.)
Rated insulation voltage
None
Rated transient protection volt. 800 V (1.2/50 µs)
60 mA @ 50 Hz/70 mA @ 60 Hz
Consumption
AC supply
DC supply
1W
Power supply AC types
Rated operational voltage
Through pins 2 & 10
220
or pins 2 & 7
120
Installation cat. III (IEC 60664)
General Specifications
Power ON time
Indication for
Power supply ON
Environment
Degree of protection
Pollution degree
Operating temperature
Storage temperature
Weight
Approval
≥
200 ms
LED, red
IP 20 B
2 (IEC 60664)
-20° to +50°C (-4° to +122°F)
-50° to +85°C (-58° to +185°F)
85 g
UL, CSA
Mode of Operation
The relay operates immedi-
ately after power supply is
applied.
When power supply is inter-
rupted, the time period starts
and at the end of the set time
the relay releases.
If power supply is reapplied
before the relay releases, the
time is reset and the relay
remains on.
B 121/B 128 monitor that
power supply is applied. If
power supply is interrupted,
the relay starts e.g. an alarm
(battery driven) after the time
period has expired.
Please note
B 128 and B 121 should not
be operated by pulses shorter
than 500 ms.
Wiring Diagrams
SPDT
8 pin
SPDT
11 pin
Power supply
B 128
Power supply
B 121
Time Setting
Knob-adjustable on scale in
seconds.
Accessories
Sockets◊
Hold down spring◊
Mounting rack
Socket cover
Potentiometer lock
S 408, S 411
HF
SM 13
BB 4
PL 1
For further information refer "Accessories".
Operation Diagram
Power supply
Relay on
2
Specifications are subject to change without notice (25.10.99)
Test/Measurement
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