CANFORD MDU AC MAINS POWER DISTRIBUTION UNITS - Sequential ON/OFF models

This range of twelve, IEC or Powercon outlet, sequential "switch-on" or "switch-on and switch-off" AC mains power distribution panels are housed in a compact 1U rackmount case. Loop-out feature models, provide an un-switched, direct loop-through power outlet to supply equipment that must remain powered when the MDU is switched off, or to supply to a second MDU. All versions have on the front panel an illuminated, power rocker switch or an un-switched neon power present indicator, fuse and LED indication of power status for each of the output channels. Inlet, outlets and Earth connection are on the rear panel.

Sequential ON

These are as the standard and switched only type but, in addition, to avoid overloading the supply, the outputs are sequentially switched on when power is applied. This delay is vital where a number of pieces of equipment drawing a high ‘inrush’ current, such as CRTs, power amplifiers or equipment fitted with switch-mode power supplies, are connected to a single MDU. This sequential solution may also be used to switch on equipment in an audio installation prior to the power amplifier to avoid ‘clicks’ and possible damage to loudspeakers.

The delay between successive outputs is preset at 300mS, but an internal control allows adjustment between approximately 30mS and 600mS. Outputs are switched using relays controlled from a microprocessor. The top cover is user-removable to access the sequential switch-on delay adjustment control. In the case of switched versions, if power is connected to the unit when the switch is 'off', no power is supplied to the outputs. If the switch is 'on', the outputs will be powered up sequentially as normal.

Sequential ON and OFF

Similar to the Sequential Switch-on types above, these also are based on the standard types, but have a control activating the 'start' or 'stop' sequence. The control is a latching rocker switch, but, it should be emphasised, does not switch the supply itself. When power is supplied to the MDU, an LED shows that power is present. If the control is in the 'stop' position, no power will supplied to the outputs. Changing the control to the 'start' position will cause the outputs to be switched on sequentially. Once the sequence is complete, changing the control to 'stop' will cause the outputs to be switched off sequentially in the reverse order.

If the control is changed to 'stop' during the 'start' sequence, the sequence is stopped and the outputs which are on will be turned off, sequentially, in reverse order. If the control is changed to 'start' during the 'stop' sequence, the outputs which have been turned off will be turned on again sequentially, in the usual 'start' order.

If power is applied to the MDU when the switch is in the 'start' position, say after a power cut, the outputs will be turned on, sequentially, in the usual order. If power is taken away from the MDU when outputs are turned on, either during a sequence or not, all outputs will turn off together.

The delay between each successive output when switching on is preset at 300mS, but an internal control may be accessed by removing the top cover which allows an adjustment between approximately 30mS and 600mS. The delay between each successive output when switching off is the same as set for the switch-on delay.

NOTE: Current drawn from the ‘loop-output’ must be included in the total current calculation. Care must be taken not to exceed the maximum total load of the MDU. See tables below for individual units current rating.

The fuses on the front panel have adjacent green and red LEDs. Green illuminated indicates that the circuit is powered correctly. Red illuminated (green off) indicates that the fuse has failed.

All outputs are numbered front and rear for easy identification and a designation- strip holder with snap-on cover is fitted on the front panel. The paper strips supplied may be inserted before or after installation; 7.5mm of printable height is available. Templates for printing designation strip labels, available as a DWG file for AutoCAD and compatible applications, can be downloaded from the appropriate product page on the Canford website.

Spare designation-strip inserts (not suitable for printers) 45-3082 and spare clear covers 45-3092 are available.

Sequential ON (MDU-Q)

Switched, Sequential ON (MDU-SQ)

Sequential ON and OFF (MDU-QQ)

All types are available finished in black front panels, with a green illuminated switch or ‘input power present’ neon indicator on the front panel.

Ordering Note: MDU's with red illuminated switches, red ‘input power present’ neon indicators or grey panels are available to special order, however an MOQ may apply. Also, all fixed lead input models are available to order with custom length leads. Please contact sales for details.

A single-rod lacing-bar is fitted, which can be moved to an alternative fixing position if desired. A spare lacing bar for MDU's is available, see 42-0005.

Mating connectors are NOT included and should be ordered separately as required.

Required accessories

Input connectors

Loop-out/Output connectors

Optional accessories

Moulded mains leads: A large range are offered, see AC Mains Power Leads.
Locking, moulded, mains leads: Patented, locking IEC leads, see AC Mains Power Leads - IEC-Lock.

Technical Specification:

Switch Guard Plates

A switch guard-plate may be fitted at the time of installation or retrospectively to Canford MDUs to avoid units being accidentally switched off (or on). The central cut-out gives finger access and a clear view of the illuminated switch. Note: Different types of MDU require switch guards of different sizes, see information in descriptions, see CANFORD AC MAINS POWER DISTRIBUTION UNIT - Switch guards.

Manufactured by Canford.