 |
|
|
Click
on drawing to view large scale version
|
| |
| SmartFan
TachStrip is a modular fan speed alarm that accepts tachometer
(Hall Effect) pulses from DC or AC fans or blowers. TachStrip
monitors these pulses and generates failure alarms if air mover
speed drops below a preset trigger speed. TachStrip comprises
a strip of 6 individual alarm units bused together. The web
separating units can be cut to provide strips to handle any
quantity of fans. |
| |
| Each
unit monitors one air mover and provides alarm outputs for that
air mover. The bus distributes power to each unit and OR’s alarm
signals from each unit to provide a single alarm output if any
air mover should fail. Each alarm unit has three outputs used
to drive a logic circuit, LED, or piezo alarm. |
| |
|
Features
- Accepts open
collector or voltage source pulses from nearly any DC or
AC fan or blower
- 6 alarm unit
strips are easily separated to monitor any quantity of fans
- Distributes
power to DC air movers through same connector used to sense
pulses
- Separate alarm
outputs are provided for each fan
- Alarm channels
are OR’d providing a single alarm if any fan fails
- Trigger Speed
is adjustable by jumper to 1500, 2500, or 4000 PPM
- Permissible
power supply voltage is 5.0 VDC minimum to 25.0 VDC maximum
|
| |
| Normally
Closed (NC) Alarm Output Closed above trigger speed and
will sink 4 mA at 0.4 VDC or less. Open below trigger speed
and will accept up to 30 VDC. Referenced to fan negative terminal.
Applies nominal 12 mA to an LED connected from NC to L. |
| |
| Normally
Open (NO) Alarm Output Open above trigger speed and will
accept up to 30 VDC. Closed below trigger speed and will sink
4 mA at 0.4 VDC or less. Referenced to negative fan terminal.
Applies nominal 12 mA to an LED connected from NO to L. Applies
nominal power supply voltage to piezo alarm connected from NO
to P. |
| |
| OR’d
(OR) Alarm Output OR’d with all other alarm units in TachStrip.
Other characteristics identical to NO alarm output. |
| |
| SPECIFICATIONS |
| |
|
Part
Number
|
Supply
Voltage Range
|
Alarm
Units Per Strip
|
|
|
5
to 25 VDC
|
|
|
H109
(1)
|
Hardware
Pack
|
|
| Note:
Maximum operating temperature is 65°C; (1) per alarm unit |
| |
| INSTALLATION |
| |
|
Mounting
|
| For
TachStrip part number 015B625 to be used as separate alarms,
cut the web separating alarm units at the designed location
with ordinary cutting pliers. |
| |
| CONNECTIONS
/ JUMPERS |
|
|
Figure
1 Wiring Diagram
Click
on drawing to view large scale version
|
|
| |
| DC
Fan Connection |
| For
three wire DC fans operating at supply voltages between 5.0
and 25.0 VDC, TachStrip distributes power to the fan in addition
to accepting tachometer pulses from the fan. Connect the fan
wires to J1. Fan wires are usually color coded with red for
+, black for - and white or yellow for A (alarm). |
| |
|
The maximum current that can be distributed to the fan via header
J1 is 2.5 Amps. Normally it is necessary to connect power to
only one J2 header in a TachStrip (015B625). However, this connector
is rated at 2.5 Amps maximum. If the total current used by all
DC fans powered by TachStrip exceeds 2.5 Amps, power connections
should be made at additional + and - pins. |
| |
| DC
Fan Tachometer Signal Compatibility |
| For
most fans, the amplitude of tachometer pulses will be equal
to the voltage applied to the fan (e.g. a 12 VDC fan usually
generates 12 VDC tachometer pulses). However, some fans generate
tachometer pulses at a lower voltage (e.g. 5 VDC pulses from
a 12 VDC fan). In these cases, TachStrip must be powered with
a voltage equal to or less than the amplitude of the pulses
generated by the fan and it cannot therefore, distribute power
to the fans. |
| |
| DC
Fans Operating Above 24 VDC |
| Though
the maximum voltage that can be applied to TachStrip is 25 VDC,
it can be used with fans operating at higher voltages. In this
case, it does not distribute power to the fans. A supply voltage
equal to or less than the amplitude of the pulses supplied by
the fans is used to power TachStrip. Connect the negative fan
lead to J1:- and the fan tachometer pulse lead to J1:A. No connection
is made to J1:+. |
| |
| AC
Fan Alarm Monitoring |
| TachStrip
cannot distribute AC power to an AC fan. AC fans usually have
5 wires, 2 for power and 3 for the tachometer pulse circuit.
Connect the AC fan power leads to the rated source of power.
Connect the three tachometer pulse leads to J1. TachStrip distributes
power to run the tachometer pulse circuits within the fans.
Apply a DC voltage as specified by the fan manufacturer for
the tachometer pulse circuits at J2. |
| |
| SUGGESTED
CONNECTING HARDWARE |
| |
|
Ref.
Desc.
|
Header
on Board (1)
|
H109
Hardware Pack
|
|
Quantity
|
Description
|
Manufacturer
(1)
|
Part
Number (1)
|
|
J1
|
22-29-2031
|
|
Housing
Terminal (gold)
|
|
|
|
J2
|
22-29-2071
|
|
Housing
Terminal (gold)
|
|
|
|
|
2
|
PCB
Support
|
Richco
|
CBS-4-19
|
|
| (1)
or equivalent |
| |
| OPERATION
|
| |
| Settings
(J3) |
| Trigger
Speed (WA ): Use this jumper to set the trigger speed. Select
a trigger that is 40 to 50% of rated speed. |
|
|
| Position
15 = 1500 PPM |
| Position
25 = 2500 PPM (Factory Setting) |
| Position
40 = 4000 PPM |
| |
| Since
fan tachometer circuits are designed with one, two, or even
more pulse outputs per revolution, settings are listed in pulses
per minute (PPM) rather than revolutions per minute (RPM). Given
the fan’s rated speed (W) and number of pulses per revolution
(N), use the following formula to select the trigger speed (WA): |
| |
| WA
= W x N x 0.4 |
| |
| For
example, a 3300 RPM fan with two pulses per revolution would
have an trigger speed (WA) of |
| |
| WA
= 3300 RPM x 2PPR x 0.4 = 2640 RPM |
| |
| Since
the 2500 PPM trigger is closest, set jumper J3 to the “25” position.
The alarm trigger accuracy is +/- 20%. |
| |
| Alarm
Outputs (J2) |
| Three
alarm circuits are located on header J2. All circuits are non-isolated,
have the same electrical ratings, and are referenced to board
ground found at J2: |
| |
| ALARM
OUTPUT LOGIC |
| |
|
Alarm
Output
|
Above
Speed Trigger
|
Below
Trigger Speed
|
Power
Removed from Unit
|
|
NC
|
Short
to Ground
|
Open
Circuit
|
Open
Circuit
|
|
NO
|
Open
Circuit
|
Short
to Ground
|
Open
Circuit
|
|
OR
|
Open
Circuit
|
Short
to Ground
|
Open
Circuit
|
|
| |
| Power
for an LED alarm indication is provided by Pin J2:L via an internal
12 mADC constant current source. Power for logic gate alarm
circuitry must be provided externally. For logic circuit alarm
indication, each alarm output can sink up to 4 mA at <= 0.4
VDC. When open, a maximum of 30 VDC can be applied to each output.
Pin J2:P and J2:OR can be used for a piezo buzzer alarm output.
Below the alarm speed trigger, the board supply voltage (Vs)
will be applied to the piezo. |
| |
| Note:
L and P are positive (+); NC, NO and OR are negative (-). |
