s martfan wisp ii is designed to control small dc fans. the low voltage version includes a temperature alarm for increased safety. the high voltage version accepts a 38 to 75 vdc supply voltage range and includes a voltage limiter set to 50 vdc. wisp ii includes both a temperature sensor and control circuit packaged in a probe for conve- nient remote or on-fan mounting. the controller uses a linear operating principle, applying a smooth dc voltage to the fans. it is available for both closed-loop (temperature regulating) and open- loop (temperature compensating) applications. 28 control resources incorporated e-mail: sales@controlres.com n web: www.controlres.com wisp ii ?speed control for dc fans features specifications noise reduction typically 15 db(a) at idle speed completely self contained including sensor controls 12, 24 and 48 vdc fans low voltage version (018w1xxx) accepts a supply voltage range of 11.5 to 30 vdc and includes a temp- erature alarm output that can drive logic or a red led high voltage version (048w0xxx) accepts a supply voltage range of 38 to 75 vdc and includes a voltage limiter set to 50 vdc 70? maximum operating temperature supplied with 15 inch (24 awg) wires and mounting clamp. temperature sensor 2.00 in. (50.8mm) 3.00 in. (76.2mm) 0.5 in. (12.7mm) the wisp ii controller s power rating is sufficient to control up to three typical 120 mm fans. the low voltage version can be used with 12 or 24 vdc fans. the high voltage version is used with 48 vdc fans. 018w135 018w140 1 closed-loop types are installed near equipment exhaust, open-loop types at equipment inlet. 2 air temperature of 70? or less, air velocity of 200 ft/min or greater. see page 13 for derating above 70?. 3 above 50 vdc supply, power is linearly derated, reaching 10 watts at 75 vdc. u.s. patents 4,659,290, 4,722,699 and 5,364,026 closed-loop 11.5 - 30 vdc 20 watts 35? 40 n/a n/a 38 - 75 20 3 35 40 closed-loop open-loop 11.5 - 30 20 n/a 35?/23? 35?/23? n/a 38 - 75 20 3 open-loop 048w035 048w040 018W135P 048w035p part number supply voltage range control temperature full speed / idle speed temperatures maximum watts to fans 2 type 1 for additional information see: page 13 design considerations
operation fan speed vs. sensor temperature the relationship between fan speed, as a per- centage of full speed, and sensed temperature is shown in figure 4. full speed occurs at the control temperature (t c ). minimum speed tem- perature (approx. 50% of full speed) depends on part number. for closed loop units, the ? in figure 4 is equal to 4. for open loop units the ??in figure 4 is equal to 12. voltage regulator and limiter part nos. 048w0xxx are intended to cover telecommunications applications using supply voltages ranging from 38 to 75 vdc. wisp ii regulates minimum (idle) voltage at 26 vdc. maximum voltage applied to the fans is limited to 50 vdc. for supply voltages above 50 vdc, power is linearly derated based on the curve shown in figure 5. 40 50 60 70 20 w power rating vs. supply voltage 10 w vdc 29 control resources incorporated e-mail: sales@controlres.com n web: www.controlres.com wisp ii ? installation & operation installation mounting mount wisp ii in a moving air stream using the cable clamp supplied. avoid placing the sensor (located at the tip) near a hot component as this may result in heating by radiation. to minimize heating of the sensor by the wisp ii circuits, avoid mounting the unit vertically with the sensor at the top. location install a closed-loop unit at or near the equip- ment exhaust where it can sense any upstream event that could affect cabinet temperature. install an open-loop (p suffix) unit at or near the equipment inlet. temperature alarm output for part nos. 018w1xxx, a temperature alarm signal is available through the yellow and black wires. an alarm can be indicated using an external led (figure 1) or logic circuit (figure 2). alarm type: non-isolated open-collector trigger: 10? above control temperature alarm states: conducting (closed), above trigger cut-off (open), below trigger max. voltage: 30 vdc max. current 4 ma dc at 0.4 vdc (logic circuit), 10 ma dc (led circuit) t ? c c t 50% 100% fan speed vs. sensor temperature - x? resistor (r1) = (vs -2)/ 10, kohms black white yellow red led r1 vs supply voltage + - black yellow white red vs supply votlage v1 logic voltage r2 va r2 >= v1 / 4, kohms + - above trigger: va <= 0.4vdc below trigger: va = v1 vs supply voltage red black white + - figure 4 fan speed vs sensor temperature figure 5 power derating curve figure 1 connection diagram for p/n 018w0xx with led temperature alarm indication. figure 2 connection diagram for p/n 018w0xx with logic circuit temperature alarm indication. figure 3 connection diagram for p/n 048w0xx and p/n 018w1xx when the temperature alarm output is not used. connections
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