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| Anti-Icing Heaters |
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New: Internal Anti-Icing Heater Option: /HE-4
- Recommended for high accuracy applications where "First Class" perfomance must be maintained (Windpower/MEASNET etc)
Our A100 Series Anemometers and W200 Series Windvanes can optionally be fitted (during manufacture) with the new /HE-4 internal anti-icing heater to help alleviate problems due to icing conditions.
Because the /HE-4 heater is fitted inside the instrument, anti-icing effectiveness is improved (compared to the HE-1 and HE-2), there are NO extra cables and NO change to the instrument shape, dimensions or appearance (however a slightly thicker instrument cable may be fitted).
This means that fitting the /HE-4 heater option does not affect the airflow around the instrument, so the calibration and characteristics of the instrument remain unaffected (unlike the external /HE-1 and /HE-2 heater types). For this reason, the /HE-4 heater is recommended for applications requiring the highest accuracy where an anti-icing heater is also necessary.
The /HE-4 heater is fitted inside the instrument extension tube ("stem") and is rated at 6W (24V supply, 250mA current). Power is supplied to the heater element via two extra/spare cores in the standard instrument cable. When /HE-4 heaters are fitted to both an anemometer and windvane, the pair will consume around 12 Watts (approximately 500mA). This is sufficient to keep the shaft/bearings free from ice under most conditions, however extreme conditions can still result in a build-up of ice/snow on the unheated rotor cups that will degrade accuracy/calibration.
The /HE-4 is available as a 24V version as standard, a "/HE-4/12V" version for 12V operation (also 6W rated, 12V supply, 500mA current) is now available too. Note that there is NO controller/thermostat built-in to the heater - it must be controlled by your logger or other equipment you supply.
External/Retro-fit Anti-Icing Heater Options: /HE-1 and /HE-2
- (NOT recommended for high accuracy or "First Class" applications)
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Our A100 Series Anemometers and W200 Series Windvanes can be fitted with external anti-icing heaters, HE-1 and HE-2 (either during manufacture or as a retro-fit kit) to alleviate problems caused by icing conditions. There is a small effect on the accuracy/calibration of anemometers when a heater is fitted to them.
These heaters are fitted to the outside of the instrument extension tube ("stem") and dissipate approximately 6 Watts each when connected a 12V (HE-1) or 24V (HE-2) power supply with some sort of thermostat/controller. Power is supplied to each heater via an additional cable (not via the standard instrument cable).
6 watts per instrument is sufficient to keep the shaft/bearings free from ice under most conditions, however extreme conditions can result in a build-up of ice/snow on the rotor cups which will affect accuracy/calibration (or could even stop the rotor in extreme cases).
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Anti-icing heaters are not usually practical if the installation is battery or solar powered due to the high power requirements. The heaters are rated at 6 Watts per instrument, that is to say an anemometer and windvane pair which are both fitted with heaters will consume around 12 Watts (1 Amp with 12V/HE-1 or 500mA with 24V/HE-2).
The resistance of long cables will be significant compared to the heater resistance (HE-1 is around 24 Ohms, HE-2 is around 96 Ohms) - the use of the HE-2 heaters with a 24V supply is advisable if long cables are involved in an installation.
There is no controller/thermostat built-in to these heaters, however many applications involve the use of a data logger or PLC which have relays which are capable of switching these heaters on/off as required. One of our T351 temperature screen/probes may be suitable for such a data-logger/PLC to measure the air temperature to gauge the need for heating.
Notes:
Specifications correct at time of writing and may change without notice. Contact us to confirm latest specifications.
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Windspeed Limited (trading as Vector Instruments),
115 Marsh Road, RHYL, North Wales, LL18 2AB, United Kingdom
Tel: +44 (0) 1745 350700 Fax: +44 (0) 1745 344206
Email: sales@windspeed.co.uk
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Website design and content is copyright (c) 2003-2010 Windspeed Limited (unless otherise stated). All trademarks are acknowledged.
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A100 Series Anemometers