Preventing False Signals

We developed the Induced Voltage Suppressor (IVS) with the intent of preventing false signals being displayed to the road users when approaching a signalized traffic intersection. This product is used in circuit with a traffic signal lantern powered by mains ac voltage when connected to a traffic signal controller such as the Philips PSC series or PTF Type Controllers connected to LED Lanterns, but it can be used with any brand of traffic signal controller.

How it works

The product addresses a common problem with many traffic signal installations with long cable runs from the Traffic Signal Controller to each corner or location of traffic signal lanterns. These cables often run in the same physical enclosure underground in conduit and thus run in parallel. The geometry predisposes the cables to having voltage induced from a cable carrying mains AC power to one that does not carry an active mains AC power. So if cable A is powered and cable B is meant to be OFF, cable B can often show a significant voltage (in the range of 30VAC to 80V AC with low current). The signal lantern attached to cable B can actually start to display a dim "glow" as if it was turned on, when in fact, it should be OFF.

The IVS is designed to prevent the incorrect signal from being displayed to road users and potentially cause the Traffic Signal Controller to "sense" a voltage on "Conflicting Phases" which would result in a SCATS Compliant Controller to shut down and go into FAULT mode and the signal flashing amber (in Australia). The IVS also prevents the audio tactile units connected to a Traffic Signal Controller from switching off if the induced voltage rises above 35V AC.

The IVS unit has switchable load elements that when a sufficient voltage is present will cause a low impedance load to be switched in limiting the rise of a voltage (less than 100V AC) along the signal cable that has been induced due to electromagnetic coupling from a nearby cable that is powered by mains AC voltage.

What voltages can IVS be used with?

All commonly used mains ac voltages including 240V AC/ 230V AC / 220V AC. The IVS will "switch itself in" up to 100V AC and dissipate any "induced voltage" and above 100V AC will allow the normal signal lantern to switch on.

What Traffic Signal Controllers can the IVS be used with?

All brands of traffic signal controllers for use world wide. This device is independent of ATC's Traffic Signal Controller products.

Can the IVS be retrofitted to existing installations?

Yes. These can be added at any time, to new installations or existing ones.

Contact Us

For more information about buying Induced Voltage Suppressors, please click here to request a quote.