Info!! How Does The Ac Neglect Indicate Function Inward A Ability Supply?

I was lately talking to ane of our Design Engineers most my weblog together with he suggested a clarification of the functioning of the air conditioning Fail signal would locomote a adept topic.  He stated that he was oftentimes asked “at what input voltage does the air conditioning Fail signal operate?”

Influenza A virus subtype H5N1 ability supply’s air conditioning Fail signal is used to provide a alert to the user that the air conditioning input ability has either been lost, or is dropping inwards voltage to a quest that the ability render volition shortly no longer locomote able to regulate or provide power.

Customers using such a signal volition together with then convey a brusque catamenia of fourth dimension (typically five to 10ms) inwards which to shop whatever information or starting fourth dimension an orderly shutdown of their system.

Internal to the ability supply, the air conditioning Fail circuit is unremarkably a unproblematic circuit comparison a reference alongside the voltage of a primary side housekeeping supply.  In the outcome that voltage drops, get is removed from an opto-coupler together with the user provided alongside an air conditioning Fail signal soil change.

Before the widespread work of Power Factor Correction (PFC), the air conditioning Fail did indeed operate at a ready input voltage.  I recollect equally a Test Technician reducing the input voltage alongside a variable transformer (variac) to banking concern gibe the function.

On those non PFC ability supplies, the air conditioning input is peak rectified equally shown below.  The principal switching converter operates off that unregulated high voltage buss, the value of which is a straight business office of the air conditioning input voltage – betwixt 120 together with 375VDC.

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On ability supplies alongside PFC though, that high voltage osculate is regulated using a boost circuit – to approximately 360VDC.  Now whatever alter to the air conditioning input voltage (within the normal operating range) is non reflected inwards a alter inwards the DC buss; thence a unlike exam method must locomote used.

Use a storage oscilloscope to monitor the output voltage, the air conditioning Fail signal together with if desired, an isolation transformer to display the air conditioning input voltage.

Turn off the input voltage together with mensurate the fourth dimension betwixt the air conditioning Fail signal going depression together with the output voltage starting to drop.  This is the total of alert fourth dimension yous volition have.

Unlike alongside a non PFC ability supply, this alert fourth dimension volition non locomote related to input voltage.