Schneider Electric CAD50GD TeSys D Relay 5NO 125V DC

CAD50GD TeSys D control relay: what the part number tells you

The CAD50GD is a Schneider Electric TeSys D control relay: Control relay, TeSys Deca, 5NO, up to 690V, 125 VDC standard coil, screw clamp terminals. In plain terms it is a contactor-style relay with five normally open contacts, designed for control circuits rather than motor power, and its coil is rated 125 V DC. Seven Star LLC supplies the CAD50GD in Oman and the GCC as an independent supplier based in Muscat.

Reading the code against the datasheet: CAD is the TeSys D control relay series, 50 gives the 5 NO contact arrangement (five poles in both cases), and the ending GD stands for the 125 V DC coil that the datasheet lists for this reference. Neighbouring references differ only in the coil voltage or type, so the complete code decides whether the relay will fit your control supply.

Technical specifications of the CAD50GD

Coil, operating window and supply sizing for the CAD50GD

The coil is the one part that distinguishes the CAD50GD from its siblings, so it deserves the closest reading.

The 125 V DC coil is the sibling for plants and utilities whose station battery is rated 125 V rather than 110 V, a convention that follows North American practice and turns up on oil and gas sites supplied by international contractors. Matching the coil to the nominal battery voltage keeps the operating window centred on the real supply. The datasheet lists the same 5.4 W standard coil power, which at 125 V is about 43 mA.

That window runs from 0.7 to 1.25 Uc, about 87.5 to 156 V on this coil, so it tolerates both a discharged battery and a boost-charged one. The drop-out band of 0.1 to 0.25 Uc is about 12.5 to 31 V. Because the relay has five normally open poles and no normally closed ones, it is used where one signal has to be repeated to many circuits, for example a generator or compressor trip fanning out to alarm, shutdown and indication, and not where a normally closed contact is needed.

Calculated from the datasheet, the 125 V DC coil of the CAD50GD has an operational window of 87.5 to 156 V (0.7 to 1.25 Uc), and it drops out at 12.5 to 31.2 V (0.1 to 0.25 Uc). The datasheet gives 5.4 W for inrush and for hold-in, which corresponds to about 43.2 mA at pull-in and when held in at the nominal voltage. These are indicative figures worked out from the stated power and voltage, and they are meant for supply sizing, not as guaranteed current ratings.

Contact arrangement of the CAD50GD: five normally open contacts

The 5 NO configuration is the version for pure signal multiplication. With no normally closed contacts, all five poles close when the coil is energised, so a single command can start, indicate and permit several circuits at once. The datasheet lists operating times only for the normally open contacts, as there are no normally closed contacts to describe.

Choose it when a single initiating contact, for example a PLC output or a protection relay trip contact, has to be repeated on five independent circuits: alarm annunciation, a shutdown loop, a remote indication, an interlock to another panel and a counter or logger. If any of those circuits needs a contact that opens when the relay operates, the 3 NO + 2 NC member of the family is the right choice instead.

Contact data from the datasheet apply to all five poles: 10 A conventional thermal current at 60 °C, utilisation categories AC-15, AC-14 and DC-13, a rated operational voltage up to 690 V AC, and a minimum switching capability of 17 V and 5 mA, which makes the contacts suitable for low-level signals as well as for 24 V PLC inputs.

Where the CAD50GD sits in the CAD50 family

The CAD50GD is one member of a family of TeSys D control relays that share the housing, the contact data and the mounting. Only the coil voltage and type change from one reference to the next, together with the contact arrangement: the CAD32 series is 3 NO + 2 NC and the CAD50 series is 5 NO. The table lists the CAD50 references we are asked for most.

If the supply is not in the table, ask us; the CAD32 series has the other contact arrangement. AC-coil versions are 84 mm deep and DC-coil versions 93 mm, which matters in a shallow enclosure.

Selection checklist for the CAD50GD

• Coil: 125 V DC, confirmed from the supply drawing or the nameplate of the relay being replaced.
• Contacts: five normally open contacts, matched to the interlock and signalling circuits.
• Supply sizing: about 43.2 mA continuously, because the datasheet gives the same power for inrush and hold-in (derived figure).
• Window: operates within 87.5 to 156 V (0.7 to 1.25 Uc) and releases at 12.5 to 31.2 V (0.1 to 0.25 Uc).
• Contact load of the CAD50GD: 10 A thermal, AC-15, AC-14 or DC-13 duties; use a contactor for motor-power loads.
• Space: 77 mm high, 45 mm wide and 93 mm deep.
• Environment: operation up to 60 °C, up to 70 °C with derating; storage -60 to 80 °C.

Mounting, wiring and service life of the CAD50GD

Mount the CAD50GD on a 35 mm DIN rail or on a plate; the datasheet lists both. It measures 77 mm x 45 mm x 93 mm and weighs 0.58 kg, so allow space for the wires to bend at the terminals and for air to circulate around the housing. Tighten the screw-clamp terminals to 1.7 N.m with a Philips No 2, Pozidriv No 2 or 6 mm flat screwdriver, and do not exceed the cable sizes of 1 to 4 mm² per terminal listed in the datasheet.

Commissioning is simple: energise the coil at nominal voltage, verify that all five poles move together, and check the contact action with a meter before connecting the field loads. The mechanical durability is 30 million cycles and the maximum operating rate is 180 cycles per minute, so in normal control duty there is no routine wear item to schedule. In a dusty site, clean the panel and check terminal tightness during planned shutdowns, because loose terminals, more often than the relay itself, cause intermittent faults.

Where the CAD50GD is used in Oman and the GCC

A 110, 125 or 220 V DC coil is a substation and power-plant part. In the utilities, desalination plants and large industrial sites of the region, the station battery feeds protection and control, and a multiplying relay of this kind repeats trip, alarm and interlock signals inside switchgear panels and relay rooms. It is a natural spare for outage planning, because panel relays at that voltage are hard to buy quickly when a shutdown is under way.

For the CAD50GD, that means five normally open contacts from one 125 V DC command, sitting next to LC1D contactors of the same TeSys D family on the same rail.

Information to send with an RFQ for the CAD50GD

• Full reference CAD50GD and the quantity
• The coil voltage and type seen on the supply drawing or on the old relay nameplate
• The load or circuit each contact will switch (voltage, current, signal level)
• Panel or machine the relay must fit, and whether it is a spare, a replacement or a new installation
• Delivery location in Oman or the GCC and the date required

Documents and quotation

A datasheet for this product is attached on this page. It lists the electrical, mechanical and environmental data summarised above, and it is worth reading beside the panel drawing before you order.

Send us the part number, quantity and application and we will confirm availability and a quotation. Seven Star LLC is an independent supplier in Muscat and is not affiliated with the manufacturer.