To understand what a voltage stabilizer is, we need to understand the basic operation of electrical equipment. Every electrical equipment is designed to operate over a range of input voltage. Depending on the sensitivity of the equipment, the working voltage range can be ± 10 percent, while specific sensitive devices may have a ± 5 percent tolerance range. For example, domestic supply voltage in Kenya is rated at 240V, but most equipment and appliances can safely operate in a range of between 230V – 250V on the higher side.
Now it is common for voltage fluctuations to happen, where the voltage can either rise or fall beyond the acceptable range. This can be caused by electrical faults in the supply line, faulty wiring or external factors such as lighting. When these fluctuations happen and go beyond the acceptable ranges, they can cause a damage to your equipment and devices. It is not uncommon to have voltage spikes after a power outage, which commonly results in burn equipment and appliances.
In order to protect sensitive (and usually expensive) equipment from damage as a result of consistent voltage fluctuations, a voltage stabilizer is used. The stabilizer regulates the fluctuating input voltage before it’s fed to the equipment to ensure that the voltage is within the acceptable range. For single phase systems, the output voltage from the stabilizer will generally be maintained at between 220V – 250V, while in three-phase supply the range is between 380 – 430V range.
How to choose the right Voltage Stabilizer
Now that you know the function of a voltage stabilizer, the next question then becomes how to choose the right one given that there are so many in the market. The basis of selecting the right voltage stabilizer for your application should be guided by the following:
(1) Whether the equipment uses single phase or three-phase
Voltage stabilizers come both in single phase and three phase systems. For most domestic applications, the supply will most likely be a single-phase system, though it is not uncommon to find homes with three-phase supply, especially for large homes. Also, determine at what point you want to do the voltage stabilization. You may have a three-phase system, but you may not want to stabilize the entire supply but a single load that runs on single phase. In this case you’ll use a single-phase voltage stabilizer even though the main supply is 3-phase. Once you know your power supply then you can go for the appropriate stabilizer.
(2) Power rating of the equipment load you want to protect
Voltage stabilizers are rated based on the size of the load it can support. The rating of the voltage stabilizer should be greater than that of the equipment. For example, if the voltage stabilizer will be used for an X-ray equipment rated at 32 kW, the stabilizer rating should be larger than that. In order to know the power rating of the equipment look at the nameplate to know the Watt (W) or KVA rating. This information is also available in the datasheet or manual of the equipment. Stabilizers are commonly rated in KVA, and is therefore important to know the KVA rating of the equipment. You can do this by simply dividing the power (in Watts) by the power factor of the equipment, which should be on the equipment nameplate or manual or datasheet. A common rule of thumb is to size the stabilizer at 25% of the equipment rating. For the above equipment rated at 32 kW, the first step is to know its KVA rating. Assuming a power factor of 0.8 as given in the manual, the KVA rating for the X-ray machine will be 40 KVA (32 divided by 0.8). After getting the KVA rating of the equipment, the next step is to determine appropriate size of the voltage stabilizer. The suitable size of the voltage stabilizer will be 50 KVA (25% higher than the 40 KVA).
(3) Sensitivity of the appliance/equipment you want to protect
There are different voltage stabilizer technologies and configurations available, and the specific type to use will be will depend on the type of equipment. Generally, more sensitive electronic equipment like computers, servers and medical equipment have little tolerance for voltage fluctuations and will require a stabilizer with high sensitivity and small ranges. In this case, a Static Voltage Stabilizer (SVS) would be the ideal type to use compared to a servo-controlled voltage stabilizer. It uses power electronic converters for voltage regulation and it produces excellent voltage regulation typically in the ±1 percent range. If the voltage stabilization is for a motor-based load, then a servo voltage stabilizer would be the right one to use.
(4) Price range of a good voltage stabilizer
The price of a voltage stabilizer will depend on all the factors listed above. Three-phase stabilizers will generally be more expensive than single-phase stabilizers. 3-phase voltage stabilizer price in Kenya will range between KSh. 250,000 for a 20KVA system upto KSh. 1.3 million for a 100 KVA voltage stabilizer.
Other factors that will determine the overall price include location of the facility to be installed, the electrical requirements for the installation among others. Generally speaking, stabilizer price in Kenya has been going down in the recent past owing to development in the markets and availability of options from different vendors.
In conclusion, voltage stabilizers are important in ensuring protection for equipment from harmful fluctuations that are common in most electrical supply. For homes and other domestic applications, small voltage stabilizers and guards are a great use for protecting electronics like Tv and music systems, as well as fridges and freezers. For commercial applications, a three-phase voltage stabilizer that is properly designed and sized is an important part of the stabilization in order to ensure your equipment are protected from fluctuating power supply.
At Support.KE we are committed to ensuring that your power is in top notch condition. We offer troubleshooting, repairs, preventive maintenance & installation services for voltage stabilizers that are customized for your system. Get support today. Call us toll-free on 0800 211 245.