CHAPTER 2

TIP: Since M’elodie does not require a dedicated neutral, it can tolerate elevated volt-

ages from ground and can be connected between line-line terminals in a 120 V 3-phase Wye system. This results in 208 V AC between lines (nominal) and will therefore draw less current for the same output power compared to operating M’elodie from 120 V AC (line-neutral). Make sure that the voltage remains within M’elodie’s recommend operating window

(180 V AC to 250 V AC). The ground terminal must always be used for safety and the line to ground voltage should never exceed 250 V AC (typically there will be 120 V AC from line to ground in the above example).

After applying AC power, the proper operating voltage is automatically selected, but the system is muted. During the next three seconds the following events occur:

1.The main power supply slowly ramps on.

2.The green Active LED on the user panel lights up, indicating that the system is enabled and ready to pass audio signals.

CAUTION: If the Active LED does not illuminate or if the system does not respond

to audio input after 10 seconds, remove AC power immediately. Verify that the voltage is within the proper range. If the problem persists, please contact Meyer Sound or an authorized service center.

If voltage drops below the low boundary of either safe operating range (brownout), M’elodie uses stored energy to continue functioning briefly, and shuts down only if voltage does not rise above the low boundary before M’elodie’s storage circuits are depleted. How long M’elodie will continue to function during brownout depends on the amount of voltage drop and the audio source level during the drop. If the voltage increases above the upper boundary of either range, the power supply rapidly turns off to prevent damage to the unit.

NOTE: If voltage fluctuates within either operating range, automatic tap selection stabilizes the internal operating voltage. This tap

selection is instantaneous, and there are no audible artifacts.

If M’elodie shuts down due to either low or high voltage, its power supply automatically turns on again after three seconds if the voltage has returned to either normal operating window. If the M’elodie loudspeaker does not turn back on after 10 seconds, remove AC power immediately (see previous Caution).

NOTE: It is recommended that the supply be operated in the rated voltage windows at

least a few volts away from the turn on/off points. This ensures that AC voltage variations from the service entry — or peak voltage drops due to cable runs

— do not cause the amplifier to cycle on and off.

CURRENT REQUIREMENTS

The M’elodie loudspeaker presents a dynamic load to the AC mains, which causes the amount of current to fluctuate between quiet and loud operating levels. Since different cables and circuit breakers heat up at varying rates, it is essential to understand the types of current ratings and how they correspond to circuit breaker and cable specifications.

The maximum long-term continuous current is the maximum rms current during a period of at least ten seconds. It is used to calculate the temperature increase in cables, in order to select a cable size and gauge that conforms to electrical code standards. It is also used to select the rating for slow-reacting thermal breakers.

The burst current is the maximum rms current during a period of approximately one second, used to select the rating of most magnetic breakers and to calculate the peak voltage drop in long AC cables according to the formula:

V pk (drop) = I pk x R (cable total).

This rating is also used to calculate the looping capabilities of M’elodie.

The ultimate short-term peak current is used to select the rating of fast-reacting magnetic breakers

Use Table 2.2 below as a guide when selecting cable gauge size and circuit breaker ratings for your operating voltage.

Table 2.2: M’elodie Current Ratings

Current Draw

115 V AC

230 V AC

100 V AC

Idle current

.680 A rms

.360 A rms

.760 A rms

 

 

 

 

Max. long-term

2.3 A rms

1.2 A rms

2.6 A rms

continuous

 

 

 

(>10 sec)

 

 

 

 

 

 

 

Burst current

4 A rms

2 A rms

4.5 A rms

(1 sec)

 

 

 

 

 

 

 

Ultimate short-

13 A pk

6.5 A pk

15 A pk

term peak

 

 

 

 

 

 

 

CAUTION: When looping M’elodie loud- speakers, always take into account the cur-

rent draw of all the speakers looped in the circuit, including the first unit, to select the cable gauge that will avoid voltage drops.

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