Question

1. With regards to electrical noise and inductive coupling, explain the purpose of running current carrying conductors in their own raceway separate from signaling cables. Does the type of raceway material, ferrous vs non-ferrous make difference?

2. When it comes to load switching on power systems, transients are unavoidable. Discuss how switching on and off inductive and capacitive loads contribute to this problem.

3. List two materials commonly used in TVSS (Transient Voltage Surge Suppressors). As well,

UL 1449 uses 3 categories when rating Surge Protective Devices (SPD) / Transient Voltage Surge Suppressors (TVSS). List the categories and explain how they apply to a TVSS’s performance.

4. In the case of the vibrating transformer, discuss the following;

• detection method used to find the problem,
• the problem itself,
• what can be repaired on the transformer or external equipment to prevent the vibrating and buzzing noise?

Answer 1

Answer 3

The components used to reduce or limit high voltage usually includes MOV, Gas Discharge Tube, Silicon Avalanche Diode, etc. or combinations of these components. Each of these components is different features

power surges can vary in both their behavior as well as their origination point, different types of surge protectors are designed to guard against different threats. Some people just protect themselves against the most common threat, while others choose to create a more comprehensive system.

Surge protectors are categorized based on their installation location, and the service area they protect. They can vary in both cost and installation method, so it’s not always necessary (or viable) to have all three, but it is important to understand how they can work together.



Type 1: Service Entrance Surge Protectors

These are the largest and most durable type of surge protectors. They have to be installed before the main breaker on your house. Power leaves the main distribution transformer, enters the surge protector, and only then flows through to your main breaker panel. This protects against destructive surges originating from elsewhere on the power grid, and have the highest surge capacity of any type.

Type 2: Whole Home Surge Protectors

This type of surge protector is similar in design to a type one, but can be user installed. These go inside of your main breaker They can be configured to protect a single circuit, or they can protect all of the circuits in your home. They guard against both larger surges as well as smaller ones, although the specifics of their behavior depends heavily on the model. Because these are commonly purchased by consumers


Type 3: Receptacle Surge Protector

This will be the type of surge protector that you are most familiar with. Receptacle surge protectors are inexpensive and easy to install.
The most common form factor is a power strip. Not only does this protect a number of devices, but it lets you share a single outlet between many low-power devices. That being said, receptacle surge protectors come in a variety of form factors.

Answer 4

When transformers are rigidly (not resiliently) mounted on the floor (or any other structure supporting them), their vibration will transmit to the support structure and find its way in neighboring spaces (rooms, offices, laboratories, etc.), causing an annoying, tiring, tonal noise.

The vibration analysis method is an effective tool for detecting internal faults in transformers, via analysis of changes in the vibration response of the transformer tank. Changes in the mechanical properties of the windings and core will ultimately affect the tank vibration response

The amount of noise is generally fixed by the design of the transformer. Adjustments to a design to reduce the noise level can be made at cost, but don't expect a huge reduction in the noise level. Loading a transformer has little effect on the noise level.