Therapévei Tech

25/08/2020

Nano Diamond Battery (NDB) is a green battery made from recycled carbon-14 waste using nanotechnology that does not run out in a single user’s lifetime and i...

12/06/2020

Everybody who has been around boats long enough has probably seen a melted bilge pump due to a locked rotor and oversized fuse.
It is a classic example of Ohm’s Law (I=V/R) in action so let's see what happens here.
- If the rotor of the bilge pump motor gets locked (because of, for example, debris that got stuck in the impeller) when the bilge pump is running, the motor will begin to heat up as it will still try to turn over.
- The heat will cause the increase of the resistance (heating the conductor causes atoms to vibrate more, that makes it harder for electrons to flow)
- Now, Ohm’s Law tells us that when resistance (R) increases, the current (I) will decrease when the voltage remains constant.
- As a result, the current can drop below the rated current of the inline fuse.
- With the circuit not interrupted by the fuse, the current is still flowing, the motor is trying to spin and the heat builds up to the point where it causes the pump housing to melt.

This situation will leave the boat without the bilge pump but could also create a fire hazard.
It is worth noting that the same principles apply to all onboard DC motor (pumps, blowers, fans, etc.)

Two simple steps can help prevent this situation, save your bilge pump, and possibly even the boat:
- Always use the fuse that is rated according to the bilge pump manufacturer’s recommendations. If the fuse keeps, blowing there is a reason for that, and replacing it with higher rated fuse is not a good solution.
- Keep the bilge on your boat clean of any debris that could get into the impeller.

If you are new to marine electricity and want to learn more, follow the link below and check out our Basic Marine Electrical & Corrosion Mitigation online course:
https://abyc.elevate.commpartners.com/products/basic-marine-electrical-corrosion-mitigation

03/04/2020

ABYC Lead Instructor Mike Bonicker will review basic electrical topics and the ABYC Standards that apply to them that are generally misunderstood, misinterpr...

03/03/2020

Let us enlighten you about LED lighting!
Radio wave interference between LED lights and VHF equipment (radiotelephone, DSC, AIS) can potentially create safety hazards. Both, VHF marine radio and AIS reception could be degraded by LED lighting. It is always a good practice to keep VHF antennas and LED sources as far apart as practicable
Strong radio interference from LED sources may not be immediately evident to maritime radio users but it is possible to test for the presence of LED interference. USCG advises to use the following procedure:
1. Turn off LED light(s).
2. Tune the VHF radio to a quiet channel (e.g. Ch. 13).
3. Adjust the VHF radio’s squelch control until the radio outputs audio noise.
4. Re-adjust the VHF radio’s squelch control until the audio noise is quiet, only slightly above the noise threshold.
5. Turn on the LED light(s).
• If the radio now outputs audio noise, then the LED lights have raised the noise floor. (Noise floor is generally the amount of interfering signals/static received beyond the specific signal or channel being monitored.)
• If the radio does not output audio noise, then the LED lights have not raised the noise floor.

If you experienced similar problems we would like to hear from you!

18/02/2020

Grounding and bonding are one of the most misunderstood terms when it comes to the boat wiring.
They are often being used interchangeably but roles and requirements for bonding and grounding conductors are different.
Bonding, as ABYC defines it, is closely related to the cathodic protection, and simply means the electrical interconnection of metallic objects (such as shafts, rudder stocks, struts, etc.) which remain in common contact with water to protect against galvanic and stray current corrosion. Bonded metals are connected to an anode which is a source of cathodic protection.
Grounding conductor (AC grounding or DC grounding) is a normally non-current carrying conductor and its main role is shock and fire hazard prevention. Grounding conductor should be connected to metallic non-current currying parts of electrical components or machinery (such as a metal case) in order to provide a safe path to the ground for potential fault current. It is important, especially when sizing DC conductors, that grounding wire is able to carry full current that current-carrying conductor can supply.
To make things more interesting, DC grounding conductors may be combined with the cathodic bonding system providing all the requirements with respect to conductor size are met for each system. Otherwise, #8 gauge typical bonding conductor might not be able to carry full fault current supplied by much bigger DC positive conductor.
In the end, it is important to mention that DC grounding, cathodic bonding, the negative side of DC system and AC grounding bus are all interconnected to the engine negative terminal or the DC main negative bus as illustrated in the diagram.

31/01/2020

04/11/2019

Descomissionamento!

https://pt.wilsonsons.com.br/descomissionamento-de-plataformas/

Das 150 plataformas em águas brasileiras, 79 já estão em fase inicial de descomissionamento ou prontas para iniciar. Você sabe como isso é feito? Acompanhe.

03/09/2019

Wiring Unlimited is now available! Download it for free here: Wiring-Unlimited-EN.pdf What is Wiring Unlimited? A Victron Energy book by Margreet Leeftink, Information Developer for Victron Energy B.V. Wiring Unlimited is all about electrical wiring of systems containing batteries, inverters, charge...

11/08/2019

24/07/2019

A radiocomunicação possui uma grande importância principalmente no alto-mar, a instalação correta dos rádios VHF é extremamente necessária para a comunicação entre barcos, principalmente em situações de perigo onde é necessário o socorro.