A standard cooling fan is essentially a bladed DC motor. By varying the voltage input across the acceptable range for a fan, the speed of the fan will increase (to added voltage) and decrease (to reduced voltage); a faster fan means more air moved and thus a higher heat exchange rate.
Contact them toll-free from a Vodacom cellphone by dialing 111. Contact them toll-free from a Telkom phone by dialing 0800-111-234. Note: Telkom toll-free numbers are generally NOT toll-free when dialed from a MTN/Vodacom cellphone.
For Vodafone and ZTE branded devices connected through Vodafone, visit your local Vodafone retailer outlet or Call Vodafone Service at 777 or 0800 800 021, or contact their on-line Customer Care here. Support Forum.