-C H A P T E R

C H A P T E R 3

Installing the Electrical Supply

This chapter provides information about the electrical supply installation and the operating characteristics of the AC and DC power supply units.

The chapter contains the following sections:

Input Current, Power and Thermal Dissipation

AC Power Supply

DC Power Supply

System Switch

Powering On the System

Powering Off the System

Input Current, Power and Thermal Dissipation

The maximum input current, power and thermal dissipation for the Netra 20 are as follows:


Input Voltage	Current	Power	Thermal Dissipation
90 VAC, 47 Hz	6.86 A	755 W	2370 BTU
230 VAC, 63 Hz	2.27 A	703 W	2207 BTU
-48 VDC	16.4 A	790 W	2481 BTU
-60 VDC	13.4 A	802 W	2518 BTU

AC Power Supply

Connector

The AC server has an IEC 60320 appliance coupler for connection to mains power.

The AC power cord is the primary means of disconnection for the AC system.

AC Input

Operating Voltage and Frequency


	Minimum	Maximum
Voltage	90 V_rms	264 V_rms
Frequency	47 Hz	63 Hz

Current

Inrush

The maximum inrush current is 25 A_peak upon start up or restart after power has been removed for 60 s or longer. Circuit breakers must not be tripped by an inrush current of 25 A lasting 200 ms.

Operating

The maximum normal input line current is less than 7.2 A_rms at 100 VAC under standard test conditions.

Power Off Mode

The maximum input power of the system in power off or remote off state is less
than 30 VA.

Source Site Requirements

The site requirements for the AC power source are as follows:

Overcurrent protection devices must be provided as part of each host equipment rack.

Circuit breakers must be located between the AC source and the Netra 20 system.

Circuit breakers must not trip when presented with an inrush current of 25 A lasting 200 ms.

Note - Overcurrent devices must meet applicable national and local electrical safety codes and be approved for the intended application.

Disconnection and Isolation

The disconnect devices for servicing are defined as:

The appliance inlet on the rear of the system

The circuit breakers in the rack in which the system is mounted

The mains plug

Ensure that these remain accessible after installation.

Caution - External filtering and/or surge suppression devices may be required on the power feeds where branch circuit electromagnetic characteristics are unknown.

Overcurrent Protection

The AC outlet socket should be protected by a 15 A double-pole double-throw circuit breaker.

Chassis Enclosure Grounding

The requirements are:

One Thomas & Betts two-hole lug (part number: 54204-UB) suitable for 8 AWG conductor or UL/CSA approved equivalent having 5/8-inch pitch (torque value: 3.5 Nm maximum)

Two M5 studs and cupwasher nuts are supplied on the rear of the chassis for connection.

A Thomas & Betts crimping tool (part number: TBM 5-S), or approved equivalent to secure the lug on to the cable

An earthing bus bar that is near the equipment and easily accessible.

The safety earth path is established by the connection of the grounding conductor within the AC power cord to a reliably earthed socket outlet located near the equipment.

FIGURE 3-1 Netra 20 AC System Grounding Points

Caution - Wear an antistatic wrist strap and use an ESD-protected mat when handling components. When servicing or removing system unit components, use an antistatic wrist strap with a 10 mm press stud connection and attach the antistatic wrist strap to the press stud at the rear or front of the chassis before removing the top access cover.

Caution - Do not open the top access cover until you have powered down the system and removed the power cable.

DC Output

The maximum continuous output power rating is 500 W for single or dual input supply. The maximum continuous rating per output is shown in TABLE 3-3.


Output	Voltage (V)	Current (A)	Regulation Band (V)
1	3.3	38	3.23 to 3.43
2	5.0	48	4.85 to 5.25
3	12	10	11.40 to 12.60
4	-12	0.5	12.60 to -11.65
5	5.0	1.25	4.75 to 5.25

DC Power Supply

Connector

The DC system has two 3-position Wago connectors per power supply. The mating connectors are specified in the section Power and Grounding Connections.

To isolate the system, break all connections by opening all external circuit breakers.

DC Input


Electrical Element	Requirement
Voltage ^[1]	-48 VDC / -60 VDC
Max. operating current	12 A @ -48 VDC / 10 A @ -60 VDC
Max. inrush current	30 A @ -48 VDC / 24 A @ -60 VDC

Source Site Requirements

The DC source must be:

-48 VDC or -60 VDC nominal centralized DC power system

Electrically isolated from any AC power source

Reliably connected to earth (that is, the battery room positive bus is connected to the grounding electrode)

Rated for a minimum of 20 A per feed pair

Note - The Netra 20 DC system must be installed in a restricted access location. The IEC, EN and UL 60950 define a restricted access location as an area intended for qualified or trained personnel only and having access controlled by a locking mechanism, such as a key lock or an access card system.

Overcurrent Protection Requirements

Overcurrent protection devices must be provided as part of each host equipment rack.

Two 20 A single-pole, fast trip, DC-rated circuit breakers (one per ungrounded supply conductor) must be located in the negative supply conductor between the DC power source and the DC system.

Circuit breakers must not trip when presented with inrush current of 30 A lasting 250 ms.

Note - Overcurrent devices must meet applicable national and local electrical safety codes and be approved for the intended application.

Disconnection and Isolation

The disconnect devices for servicing are defined as:

The circuit breakers in both negative supply conductors

Both DC input connectors

FIGURE 3-2 Netra 20 DC System Grounding Points

Connection Materials

Chassis Ground

The requirements are:

One Thomas & Betts two-hole lug (part number: 54204-UB) suitable for 8 AWG conductor or UL/CSA approved equivalent having 5/8-inch pitch. Torque value: 3.5 Nm maximum. Two M5 studs and cupwasher nuts are supplied on the rear of the chassis for connection.

A Thomas & Betts crimping tool (part number: TBM 5-S), or approved equivalent to secure the lug on to the cable.

An earthing bus bar that is near the equipment and easily accessible.

Caution - External filtering and/or surge suppression devices may be required on the power feeds where branch circuit electromagnetic characteristics are unknown.

Note - It is good practice to connect the chassis grounding conductor before applying power to the system via the Wago connectors.

DC Supply and Ground Conductor

The requirements are:

Suitable conductor material: tinned copper only

Conductors: 12 AWG maximum (between the DC chassis and circuit breaker). There are three conductors:

-48V_DC/-60V_DC Supply (pin 1)

Ground connection to power supply (pin 2)

-48V_DC/-60V_DC Return (pin 3)

System ground conductor: 8 AWG

Cable insulation rating: minimum 75°C, low smoke fume (LSF), flame retardant

Cable must conform to GR63CORE fire resistance requirements

Branch circuit cable insulation color: per applicable National Electrical Codes

Grounding cable insulation color: green/yellow

Caution - Do not open the top access cover until you have powered down the system and removed the DC source from both input connectors.

DC Output

The maximum continuous output power rating is 500 W for single or dual input supply. The maximum continuous rating per output is shown in TABLE 3-5.


Output	Voltage (V)	Current (A)	Regulation Band (V)
1	3.3	38	3.23 to 3.43
2	5.0	48	4.85 to 5.25
3	12	10	11.4 to 12.6
4	-12	0.5	-12.60 to -11.65
5	5.0	1.5	4.75 to 5.25

Power and Grounding Connections

The following DC connection materials are provided in the DC input connector kit:

Two Wago DC input connectors and strain relief housings

One cage clamp operating lever

Two wire ties

FIGURE 3-3 DC Input Connector

FIGURE 3-4 Strain Relief Housings

FIGURE 3-5 Cage Clamp Operating Lever

FIGURE 3-6 shows the power connector on the DC power supply on your system.

FIGURE 3-6 Power Connector on the DC Power Supply

Wiring the DC Input Power Connector

1. Turn off power to the DC power source by opening the circuit breakers.

Caution - Do not proceed with these instructions until you have turned off the power to the DC power source through the circuit breakers.

2. Strip 8mm (0.31 inches) of insulation from each of the wires to be fitted to the connector.

Do not strip more than 8 mm (0.31 in.) from each wire. Doing so will leave uninsulated wire exposed from the DC input connector after the assembly is complete.

FIGURE 3-7 Stripping the Insulation From the Wire

3. Using a DC connector from the kit, insert the tip of a cage clamp operating lever into the rectangular hole directly above the hole in the DC connector where you want to insert the first wire and press down on the cage clamp operating lever.

This opens the cage clamp for this section of the DC input connector.

You can also open the DC connector cage clamp by inserting a small slotted screwdriver into the rectangular hole directly above the hole in the DC connector where you want to insert the first wire and pressing down on the screwdriver.

FIGURE 3-8 Opening the DC Connector Cage Clamp Using the Cage Clamp Operating Lever

4. Feed the stripped end of each wire into the appropriate hole in the DC input connector.

FIGURE 3-9 shows which wires should be inserted into each hole in the connector.

FIGURE 3-9 Assembling the DC Input Power Cable

5. Repeat Step 3 and Step 4 for the other two wires to complete the assembly of the DC input power cable.

6. If you are not using the optional strain relief housing, secure the wires together with a wire tie.

7. Repeat Step 2 through Step 6 to wire the other DC input power connector.

Note that you will require a separate DC power source for each DC input.

If you need to remove a wire from the DC input connector, insert the cage clamp operating lever or a small screwdriver into the slot directly above the wire to free the wire from the cage clamp, and press down (FIGURE 3-8).

Installing the Strain Relief Housings

1. Take the DC input connector and insert the bottom portion of the strain relief housing into the notch on the DC input connector until it snaps into place.

Make sure the strain relief housing snaps into place on the DC input connector; you will not be able to complete the assembly correctly if the strain relief housing is not snapped into place.

FIGURE 3-10 Inserting the Bottom Portion of the Strain Relief Housing

2. Route the three wires coming from the DC power source through the opening at the end of the bottom portion of the strain relief housing.

FIGURE 3-11 Routing the Wires Out of the Bottom Portion of the Strain Relief Housing

3. Insert the wire tie into the bottom portion of the strain relief housing.

FIGURE 3-12 Securing the Wires to the Strain Relief Housing

4. Loop the wire tie over the wires and back out of the strain relief housing, then tighten the wire tie to secure the wires to the strain relief housing (FIGURE 3-12).

5. Lower the three prongs on the top portion of the strain relief housing into the openings in the DC input connector, then push the top portion and bottom portion of the strain relief housing together until they snap into place.

FIGURE 3-13 Assembling the Strain Relief Housing

FIGURE 3-14 Connecting the DC Power Cable to the Netra DC Power Supply

Connecting the DC power cable to the system DC power supply.

The DC input power cables for your system are now completely assembled. FIGURE 3-14 shows how the DC input power cable will connect to the DC inlet connector.

System Switch

The system switch of the Netra 20 system functions as a standby device enabling and disabling the power module outputs. The system switch is a rocker, momentary switch.

The system does not contain any integral circuit breakers. To isolate the system from the mains power, you must remove the input power connector.

Note - The ON/STBY switch handles low voltage signals only; the high-power circuits do not pass through this switch.

Powering On the System

Prior to powering on, inspect the supply conductors for mechanical security.

Netra 20 AC System

1. Plug the system into the mains supply.

2. Momentarily set the front panel ON/STBY system switch to the ON position and hold it until the system starts to power up.

Netra 20 DC System

1. Insert both DC input connectors.

2. Close both DC circuit breakers.

3. Momentarily set the front panel ON/STBY system switch to the ON position and hold it until the system starts to power up.

FIGURE 3-15 System Power-On (Front Panel, AC System Shown)

Powering Off the System

Chapter 8 describes how to power off the system using software.

Caution - Before turning off system power, exit from the operating system. Failure to do so may result in data loss.

AC System

1. Where necessary, notify the users that the system is going down.

2. Back up system files and data.

3. Halt the operating system.

4. Momentarily set the front panel ON/STBY system switch to the STBY position until the system powers down.

5. Verify that the Power LED is off.

6. Disconnect the AC power connector from the rear of the system.

Caution - Regardless of the position of the ON/STBY switch, where an AC power cord remains connected to the system, potentially dangerous voltages could be present within the power supply.

FIGURE 3-16 System Power-off (Front Panel, DC System Shown)

DC System

1. Where necessary, notify the users that the system is going down.

2. Back up system files and data.

3. Halt the operating system.

4. Momentarily set the front panel ON/STBY system switch to the STBY position until the system powers down.

5. Verify that the Power LED is off.

6. Open both DC circuit breakers.

7. Detach both DC input connectors.

^{1 (TableFootnote) The DC power supply range is -40 VDC to -75 VDC.}