What is a UPS?
An Uninterruptible Power Supply (UPS) is a device designed to provide backup power to connected equipment in specific situations, such as when the main utility power source fails or experiences disturbances like spikes, surges, or voltage dips. The primary function of a UPS is to maintain continuous power supply to the connected load, ensuring there are no disruptions.
UPS systems are critical in many industries, particularly where high availability is essential. In such cases, any interruption in power supply can have serious consequences. Common applications of UPS systems include computer servers, data centers, laboratories, and healthcare facilities.
The reliability and efficiency of a UPS are largely determined by its batteries or battery bank. The main function of the batteries is to supply power to the connected load when the main utility AC supply fails. As mentioned earlier, UPS systems are particularly suitable for applications where electrical loads are sensitive to power loss or power quality issues.
What is a Bypass Switch?
A bypass allows the electrical load (which is usually powered by the UPS) to be directly transferred from the UPS to the main power source, effectively bypassing the UPS. Bypass switches are used in various situations, such as maintenance, testing, or UPS failure. There are two main types of bypass switches:
- Static Bypass
- Maintenance Bypass Switch (Manual Bypass)
What is a Static Bypass?
A static bypass is an automatic transfer switch that allows the load to be instantaneously and automatically transferred to the main power source without interruption under specific conditions. For example, if the UPS fails or becomes overloaded, the static bypass ensures that continuous power is supplied to the load.
The static bypass uses a control logic system in combination with electronic switches, such as thyristors, to rapidly transfer the load from the UPS to the mains power.
What is a Maintenance/Manual Bypass?
A maintenance or manual bypass is a manually operated switch that allows the load to be transferred to the main power source. This enables the UPS to be serviced or maintained without interrupting the power supply to the load.
TYE Solution reak Configuration
TYE is pleased to offer a Manual Bypass Switch solution in a Make-Before-Break (MBB) configuration, which prevents interruptions to the load during the power transfer process.
Figure 1: Operational Principal of UPS + MBB Bypass
Figure 1 illustrates the operation of the Make-Before-Break (MBB) Bypass system. Under normal conditions, the AC source powers the UPS, which in turn powers the connected load. During maintenance, the MBB bypass is activated, isolating the UPS from the system and bypassing it.
Figure 2: Schematic of UPS Bypass System
Figure 2 above highlights the transition of the UPS output to the Bypass Switch output in the Make Before Break Configuration. The details of each state are as follows:
- State 1: In this state, the load is powered solely by the UPS output. The UPS provides clean and stable AC power from its battery or internal filtering circuit.
- State 2: This state represents the transition process between the UPS supply and the bypass. In the MBB configuration, both switches are closed momentarily, ensuring continuous power supply to the load.
- State 3: In this state, the load is supplied directly from the AC source, bypassing the UPS completely. However, this unfiltered power is only used during maintenance or specific situations until the UPS can resume feeding the connected loads.