PNB – Themes & Variations

The season’s final mixed bill promises intriguing variety. Balanchine’s resplendent Theme and Variations represents the height of classical purity and elegance, while his zesty Tarantella pas de deux dazzles with virtuoso fun. In Jose Limon’s masterpiece, The Moor’s Pavane—a reduction of Shakespeare’s Othello—riveting characterizations cast a powerful spell. The line-up is joined by the return of our own Price Suddarth’s electric Signature.

Signature

Music: Barret Anspach

Choreography: Price Suddarth

Tarantella

Music: Louis Moreau Gottschalk

Choreography: George Balanchine

The Moor’s Pavane

Music: Henry Purcell

Choreography: José Limón

Variations on the theme of Othello

Theme and Variations

Music: Peter Ilyich Tchaikovsky

Choreography: George Balanchine

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PNB – A Midsummer Night’s Dream

PNB’s production of Shakespeare’s comedy charms everyone who enters its enchanted realm. Deep in a Northwest-inspired fairy kingdom, a quarrel between the King Oberon and Queen Titania sparks mayhem when mischief-maker Puck mismatches mortal lovers and causes Titania to romance donkey-headed Bottom. All’s well that ends well by Act II, which opens with Mendelssohn’s famous Wedding March and celebrates ideal love with some of Balanchine’s most beautiful choreography. Featuring the PNB Orchestra.

Music

Felix Mendelssohn

Choreography

George Balanchine

Staging

Francia Russell

Scenic & Costume Design

Martin Pakledinaz

Lighting Design

Randall G. Chiarelli

PNB – Director’s Choice

The second mixed bill of the season offers Peter Boal’s seasonal selections, handpicked to introduce the audience to dancemakers who are evolving the art form. His interest in American choreographers Robyn Mineko Williams and Matthew Neenan prompted commissions to make new works for the company. These are joined by a third new-to-PNB work by ballet superstar Justin Peck, set to a score by Sufjan Stevens.

The Trees The Trees

World Premiere

Music

World Premiere Commission

Kyle Vegter

Choreography

Robyn Mineko Williams

Words

Heather Christle

Vocalist

Alicia Walter

Bacchus

World Premiere

Choreography

Matthew Neenan

Music

Oliver Davis

In The Countenance of Kings

PNB Premiere

Music

Sufjan Stevens

Choreography

Justin Peck

Source: https://www.pnb.org/season/directors-choice/

GEL / AGM Battery – How to select power supply

Only charge GEL batteries using a confirmed and reliable, temperature sensing, voltage regulated charger. Never use a constant current charger!

  1. At 25°C/77°F keep charging current in the range of 2.38 volts to 2.42 volts per cell for GEL cell batteries.
  2. At 25°C/77°F keep charging voltage in the range of 2.4 volts to 2.465 volts per cell for AGM batteries

They are usually rated by their voltage and there start rates or the rate in amperes that the charger will supply at the beginning of the charge cycle. When selecting a charger, the charge rate should be between 10% and 30% of the battery’s 20-hour AH capacity.

For example: a battery with a 20-hour capacity rating of 100 AH should use a charger rated between approximately 10 and 30 amps (for multiple battery charging use the AH rating of the entire bank to determine the charger rating required.

The “Ideal Charge Curve”

Bulk phase: This is where the heavy lifting takes place. Charge at a rate up to 20 percent to 40 percent of the batteries capacity in amp hours to a voltage of about 14.6 volts (gel: 14.1 volts). For example, a 200 amp-hour battery would be charged at 40–80 amperes. This will bring the battery to about 75 percent of full charge, and is efficient (more amp-hours replaced per hour of charge time) since the battery accepts more current when it is discharged. AGMs require slightly different voltages, and unless there is an AGM setting, should be charged using lead-acid settings.

Acceptance phase:  Maintains battery at 14.6 volts (Gel: 14.1 volts) while the amperage is steadily reduced. This will restores the next 25 percent of capacity at a declining rate. Your battery can be considered fully charged if it will accept current equal to 2 percent of C at 14.6 volts (a 200 amp-hour battery will only accept four amps).

Float phase: When the battery’s acceptance declines to two to four percent of C, the voltage is reduced to 13.4 volts (Gel: 13.8 volts) to maintain the battery without losing electrolyte from the cells. This is a maintenance phase, not a charging phase.

Equalization: This stage is used to prevent flooded lead acid batteries from aging prematurely, and is an optional, frequently omitted phase. After the battery reaches the end of the acceptance phase, the battery continues to be charged at four percent of C until the voltage stops rising, usually around 15.5 to 16.2 volts. This forces the battery to its highest possible state of charge, boiling the electrolyte in a controlled manner and dissolving the lead sulfate crystals that have collected on the battery’s plates.

In industrial applications where maximum energy storage is important, this phase is done every charge cycle. In the marine environment, it is more likely to be done every 20–50 cycles to extend the life and capacity of wet batteries. Gel and AGM batteries should not be equalized. Since electrical equipment and light bulbs can be damaged by high voltage, the battery should be disconnected from all loads during equalization.

This type of battery charging, consisting of multiple stages, is not possible with automotive-type alternator regulators, unregulated solar panels, ferroresonant chargers, or taffrail generators. We strongly encourage the use of efficient charge devices, both for shorepower charging and alternator regulation, that use modern multiple-step regulation.

How to rapidly kill a battery

Undercharging: Consistently failing to fully recharge batteries leaves them with lead sulfate that hardens on their plates—they become sulfated—and gradually lose their ability to perform. Increased resistance when charging causes falsely elevated voltage readings, essentially fooling the battery charger, leading to further undercharging, in a downward spiral. Beyond a certain point, a sulfated battery cannot be returned to a healthy state, and you need a replacement. Keep your batteries charged, and equalize your wet cell batteries every six to eight weeks in temperate climates, and more frequently in the tropics.

Overcharging: Especially fatal to Gel and AGM batteries, consistent overcharging (NOT equalization) boils the electrolyte out of the cells, and can even lead to thermal runaway, with the battery becoming hotter and hotter. One of our writers experienced thermal runaway on his liveaboard Catalina 30, caused by a ferroresonant “dumb” charger, with nearly catastrophic results.

Excessive deep discharge: Don’t completely discharge a deep cycle battery if it can be avoided. The deeper the discharge the less life you will get from the battery. The ideal method is to charge and discharge the batteries through the middle range (50 percent to 85 percent) of their capacity and, if they are flooded batteries, to equalize them periodically. Leaving the battery in a fully-discharged state, for example during winter storage, causes it to become sulfated.

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