Ventilator la DM 800

[hotm]

Ventilatorul original avea o tensiune (12V) si un anumit curent (sau in loc de curent e data puterea P=UxI). Mai mult ca sigur noul ventilator are alte caracteristici.
Clonele noi au controler incorporat care era calibrat sa porneasca ventilatorul la un anumit prag de temp, insa electronic vorbind, aceasta decizie de fapt se face prin compararea valorii rezistentelor, care sunt foarte mult influentate de temperatura. Cu alte cuvinte tu bagand alte caracteristici de ventlaotor ai acum alt prag la care se va opri ventilatorul...pe care doar daca chinejii au fost destepti si au lasaat ceva potentiometru la vedere se poate regla...daca nu uita-te la ce am realizat eu la cloana mea (am mai pus si pe alte forumuri, insa aici nu am putut baga poze decat prin linkuri, ceea ce ma depaseste!):

Controler de ventilator pentru DM800

Pentru cei care vor sa isi puna un ventilator pe DM800 sau pentru cei care au deja (in general la clone) este necesara realizarea unui controler pentru acesta, in sensul de a functiona numai atunci cand temperatura din inauntrul boxului depaseste o anumita valoare. De exemplu daca receiverul este in stand-by acesta se raceste si nu mai este nevoie ca ventilatorul sa mai functioneze, urmand ca in momentul cand receiverul se foloseste, temperatura va creste si astfel ventilatorul sa porneasca. Realizand acest lucru, veti prelungi considerabil viata ventialtorului si veti putea dormi linistit noaptea, daca aveti receiverul in dormitor.
Am cautat si am gasit pe internet o varianta simpla pentru ventilatoare cu un consum de pana la 200mA. Mentionez ca ventilatorul initial (pe clona) avea doar 50mA.
Iata linkul> http://www.rason.org/Projects/fancont/fancont.htm


THERMAL COOLING FAN CONTROLLER

BY N1HFX

As we begin to enjoy those lazy hazy days of summer, the most important thing on most of our minds is how to keep cool during those hot days. For some of us that means turning up the old air conditioner and sipping on a nice cold glass of our favorite soft drink. However, we often forget about an equally important item and that is how to keep our rigs cool during those long winded summertime QSO's. Until recently, most VHF and UHF transceivers were sold with oversized heat sinks and no cooling fans. Even more surprising is the discovery of the mere 25% duty cycle of many of these radios. Is it any wonder that those RF power amplifier modules have such a high failure rate?

If you own one of those older radios designed before manufacturers finally realized that cooling fans were really needed, help is at hand. The circuit in figure 1 is a thermal cooling fan controller designed around the famous 741 op amp and a simple thermistor. This circuit will control a 12 volt fan requiring as much as 200 MA of current. The thermistor is used as a sensor which turns the fan on whenever the temperature exceeds 88 F. Many of the 12 volt CPU cooling fans will work just fine. Simply attach the cooling fan to the rig's heat sink and place the sensor so that it is in physical contact with the heat sink but not in the fan's air flow. Use tie wraps or some other suitable means to mount the fan and sensor. Experience has shown that soldering can damage or alter the characteristics of the thermistor. Use Butt type crimp connectors to prevent damage from soldering.

The thermistor, R1, is really the heart of this circuit. At 70 F, the thermistor has a resistance of about 10,000 ohms. As the thermistor heats up, it's resistance decreases until the voltage threshold determined by R4 is reached. At this time the output of the op amp goes from high to low causing transistor Q1 to be saturated and allowing current to flow through the emitter to the collector. Capacitor C1 acts as a filter capacitor reducing fan noise as well as providing a capacitive start for the motor. Do not omit C1 in this circuit. The value of C1 may need to be increased if fan noise becomes audible in your rig's receiver. If you would like the fan to turn on at a different temperature or can't find an 8.2K resistor in your junk box then replace R4 with a 10K trimmer pot.

DE N1HFX

Pe langa schema va prezint si rezultatul in imagini.

http://www.multiupload.com/A72QJO7D5I

Bafta la lipituri!

p.s. Faza cu oprirea ventilatorului la programele HD, e o gluma chinezeasaca! Inseamna ca temperatura crestea atat de mult incat contriolerul facut de ei primea o valoare masurata prea mare ca sa o compare si astfel controlerul intra in balarii si da semnal "0" catre ventilator.

[x-ander]

Eu am renuntat la ventilator de 6 luni. Nu am avut nici o problema!!!