Electronic equipment designed for rail and transit applications must be able to survive in an environment plagued with RF noise, high-voltage transients and sustained over-voltage conditions. Self-generated transients produced by high frequency electronic switching devices, noisy contacts and inductive coils must also be contained; often requiring individually tailored suppression circuitry to keep emissions within acceptable levels. Transient protection and suppression devices found in existing equipment are often inadequate, outdated, or improperly applied.


Engineering Report ER15012 (Transient Protection and Suppression for Rail/Transit Applications) is avaiable for download. See the "other info" in the Transzorb catagory.

	Transzorb (TVS Assemblies) Transient voltage suppressors (TVS’s or TransorbsTM) are silicon avalanche diodes that limit damaging voltage spikes through a clamping action, reducing the amplitude of the transient to a nondestructive level. TVS’s have faster response times and do not exhibit the wear-out characteristics associated with MOV’s. They are available in unipolar and bipolar versions; the later being an excellent choice for suppressing both positive and negative supply-line transients normally encountered in rail and transit applications
	Diodes Recirculating diodes help to contain inductive load transients that occur when a solenoid coil is turned off (e.g. Model 812 solenoid valve) or a motor brush breaks contact with its armature winding (e.g. SafeSet Parking Brake). They operate below TVS thresholds, keeping transients to a minimum. Recirculating diodes are however, polarity sensitive, and will blow if wired backwards, ceasing to perform their intended function, often without any indication of failure
	MOVs (Metal Oxide Varistors) Metal oxide varistors (MOV’s) are variable resistors that maintain high resistance until a voltage spike is sensed at which time their resistance decreases rapidly, creating a shunt path for the over-voltage condition.
	Electron Sentinel Combines unipolar diode with MOV.

Salem Test Light

	Test Light Salem Test Light - 6 Watt, 60VDC