Genset atau kepanjangan dari generator set adalah sebuah perangkat yang telah berfungsi dapat menghasilkan daya listrik. Disebut sebagai generator set dengan pengertian adalah satu set peralatan yang tergabung dari dua perangkat yang berbeda yaitu engine dan generator atau alternator. Engine sebagai perangkat pemutar sedangkan generator atau alternator sebagai perangkat pembangkit listrik.
Engine juga dapat berupa perangkat mesin diesel berbahan bakar solar atau mesin berbahan bakar bensin, sedangkan generator atau alternator juga merupakan kumparan atau gulungan tembaga yang telah terdiri dari stator ( kumparan statis ) dan rotor (kumparan berputar).
Dalam ilmu fisikia yang sederhana juga dapat dijelaskan bahwa engine dapat memutar rotor pada generator sehingga timbul medan magnit pada kumparan stator generator, medan magnit yang timbul pada stator dan berinteraksi dengan rotor yang berputar akan dapat menghasilkan arus listrik sesuai hukum Lorentz (ingat pelajaran fisika SMA dulu).
Arus listrik yang telah dihasilkan oleh generator akan memiliki perbedaan tegangan di antara kedua kutub generatornya sehingga apabila dihubungkan dengan beban akan menghasilkan daya listrik, atau dalam rumusan fisika sebagai
P (daya) = V (tegangan) x I (arus),
dengan satuan adalah VA atau Volt Ampere.
Rumusan fisika yang lebih kompleks lagi dijelaskan bahwa
P (daya) = V (tegangan) x I (arus) x CosPhi (faktor daya) dengan satuan Watt.
Apa saja type genset?
Genset juga dapat dibedakan dari jenis engine penggeraknya, dimana kita kenal tipe-tipe engine yaitu engine diesel dan engine non diesel /bensin. Engine diesel telah dikenali dari bahan bakarnya yang berupa solar, sedangkan engine non diesel berbahan bakar bensin premium.
Di pasaran, genset dengan engine non diesel atau berbahan bakar bensin biasa diaplikasikan pada genset yang berkapasitas kecil atau dalam kapasitas maksimum 10.000 VA atau 10 kVA, sedangkan genset diesel berbahan bakar solar diaplikasikan pada genset berkapasitas > 10 kVA. Mengapa demikian ? Hal tersebut terkait dengan tenaga yang telah dihasilkan oleh diesel lebih besar daripada engine non diesel, dimana cara kerja pembakaran diesel yang lebih sederhana yaitu tanpa busi, lebih hemat dalam pemeliharaan, lebih responsif dan bertenaga. Selain itu untuk aplikasi industri dimana bahan bakar diesel (solar) lebih murah daripada bensin (gasoline). Tulisan lebih dalam tentang cara kerja engine diesel akan kami sajikan dalam tulisan-tulisan berikutnya.
Dalam aplikasi kita akan jumpai bahwa genset yang terdiri dari genset 1 phasa atau 3 phasa, apa artinya ini ? Kita akan jelaskan lebih dalam lagi, bahwa pengertian 1 phasa atau 3 phasa adalah telah merujuk pada kapasitas tegangan yang telah dihasilkan oleh genset tersebut. Tegangan 1 phasa artinya tegangan yang telah dibentuk dari kutub L yang mengandung arus dengan kutub N yang tidak berarus, atau berarus Nol atau sering kita kenal sebagai Arde atau Ground. Sedangkan tegangan 3 phase telah dibentuk dari dua kutub yang bertegangan. Genset tiga phasa dapat menghasilkan tiga kali kapasitas genset 1 phasa. Pada sistem kelistrikan PLN kita, kapasitas 3 phasa yang dihasilkan untuk aplikasi rumah tangga adalah 380 Volt, sedangkan kapasitas 1 phasa adalah 220 Volt.
Daya listrik dalam ilmu fisika juga merupakan besaran vektor, artinya besaran yang telah memiliki besar dan arah, tegangan dan arus yang telah dihasilkan juga merupakan gelombang sinusoidal dengan frekuensi tertentu. Di Indonesia, frekuensi tegangan dan arus telah ditetapkan sebesar 50 Hz, dimana hal ini mengikuti standar frekuensi di Belanda atau negara-negara Eropa, sedangkan di negara Amerika Serikat dan Kanada menggunakan frekuensi 60 Hz.
Baltimore Residents Away From Turmoil Consider Their Role
BALTIMORE — In the afternoons, the streets of Locust Point are clean and nearly silent. In front of the rowhouses, potted plants rest next to steps of brick or concrete. There is a shopping center nearby with restaurants, and a grocery store filled with fresh foods.
And the National Guard and the police are largely absent. So, too, residents say, are worries about what happened a few miles away on April 27 when, in a space of hours, parts of this city became riot zones.
“They’re not our reality,” Ashley Fowler, 30, said on Monday at the restaurant where she works. “They’re not what we’re living right now. We live in, not to be racist, white America.”
As Baltimore considers its way forward after the violent unrest brought by the death of Freddie Gray, a 25-year-old black man who died of injuries he suffered while in police custody, residents in its predominantly white neighborhoods acknowledge that they are sometimes struggling to understand what beyond Mr. Gray’s death spurred the turmoil here. For many, the poverty and troubled schools of gritty West Baltimore are distant troubles, glimpsed only when they pass through the area on their way somewhere else.
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Officers blocked traffic at Pennsylvania and West North Avenues after reports that a gun was discharged in the area.Credit Drew Angerer for The New York Times
And so neighborhoods of Baltimore are facing altogether different reckonings after Mr. Gray’s death. In mostly black communities like Sandtown-Winchester, where some of the most destructive rioting played out last week, residents are hoping businesses will reopen and that the police will change their strategies. But in mostly white areas like Canton and Locust Point, some residents wonder what role, if any, they should play in reimagining stretches of Baltimore where they do not live.
“Most of the people are kind of at a loss as to what they’re supposed to do,” said Dr. Richard Lamb, a dentist who has practiced in the same Locust Point office for nearly 39 years. “I listen to the news reports. I listen to the clergymen. I listen to the facts of the rampant unemployment and the lack of opportunities in the area. Listen, I pay my taxes. Exactly what can I do?”
And in Canton, where the restaurants have clever names like Nacho Mama’s and Holy Crepe Bakery and Café, Sara Bahr said solutions seemed out of reach for a proudly liberal city.
“I can only imagine how frustrated they must be,” said Ms. Bahr, 36, a nurse who was out with her 3-year-old daughter, Sally. “I just wish I knew how to solve poverty. I don’t know what to do to make it better.”
The day of unrest and the overwhelmingly peaceful demonstrations that followed led to hundreds of arrests, often for violations of the curfew imposed on the city for five consecutive nights while National Guard soldiers patrolled the streets. Although there were isolated instances of trouble in Canton, the neighborhood association said on its website, many parts of southeast Baltimore were physically untouched by the tumult.
Tensions in the city bubbled anew on Monday after reports that the police had wounded a black man in Northwest Baltimore. The authorities denied those reports and sent officers to talk with the crowds that gathered while other officers clutching shields blocked traffic at Pennsylvania and West North Avenues.
Lt. Col. Melvin Russell, a community police officer, said officers had stopped a man suspected of carrying a handgun and that “one of those rounds was spent.”
Colonel Russell said officers had not opened fire, “so we couldn’t have shot him.”
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Lambi Vasilakopoulos, right, who runs a casual restaurant in Canton, said he was incensed by last week's looting and predicted tensions would worsen.Credit Drew Angerer for The New York Times
The colonel said the man had not been injured but was taken to a hospital as a precaution. Nearby, many people stood in disbelief, despite the efforts by the authorities to quash reports they described as “unfounded.”
Monday’s episode was a brief moment in a larger drama that has yielded anger and confusion. Although many people said they were familiar with accounts of the police harassing or intimidating residents, many in Canton and Locust Point said they had never experienced it themselves. When they watched the unrest, which many protesters said was fueled by feelings that they lived only on Baltimore’s margins, even those like Ms. Bahr who were pained by what they saw said they could scarcely comprehend the emotions associated with it.
But others, like Lambi Vasilakopoulos, who runs a casual restaurant in Canton, said they were incensed by what unfolded last week.
“What happened wasn’t called for. Protests are one thing; looting is another thing,” he said, adding, “We’re very frustrated because we’re the ones who are going to pay for this.”
There were pockets of optimism, though, that Baltimore would enter a period of reconciliation.
“I’m just hoping for peace,” Natalie Boies, 53, said in front of the Locust Point home where she has lived for 50 years. “Learn to love each other; be patient with each other; find justice; and care.”
A skeptical Mr. Vasilakopoulos predicted tensions would worsen.
“It cannot be fixed,” he said. “It’s going to get worse. Why? Because people don’t obey the laws. They don’t want to obey them.”
But there were few fears that the violence that plagued West Baltimore last week would play out on these relaxed streets. The authorities, Ms. Fowler said, would make sure of that.
“They kept us safe here,” she said. “I didn’t feel uncomfortable when I was in my house three blocks away from here. I knew I was going to be O.K. because I knew they weren’t going to let anyone come and loot our properties or our businesses or burn our cars.”
