Schneider Electric CAD32ED TeSys D Relay 3NO+2NC 48V DC

CAD32ED control relay with a 48 V DC coil

Control circuits that need five switching points from one command often turn to the CAD32ED, a Schneider Electric TeSys Deca control relay with three normally open and two normally closed contacts and a 48 V DC coil. The manufacturer describes it as: TeSys D control relay – 3 NO + 2 NC – up to 690 V – 48 V DC standard coil. Seven Star LLC supplies the CAD32ED in Oman and the GCC as an independent supplier based in Muscat.

The code is easy to decode once you know the pattern. CAD32 sets the five-pole contact block (three normally open and two normally closed contacts), the letter E marks 48 V, and the closing D marks a standard DC coil. The datasheet confirms this reference as a 48 V DC coil version.

Using three normally open and two normally closed contacts on the CAD32ED

Use the normally closed contacts for permissive and interlock loops that must fall away on operation, such as stopping a second starter while the first is running, or for a healthy-state signal that drops out when the relay operates. The normally open contacts are available to repeat start, run and trip signals. If a circuit needs more than three normally open contacts and no normally closed ones, the 5 NO version of the same family is the better match.

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.

Datasheet values for the CAD32ED

How the 48 V DC coil of the CAD32ED behaves

The coil is the one part that distinguishes the CAD32ED from its siblings, so it deserves the closest reading.

A 48 V DC coil points to a telecom-style or battery-backed supply. Many remote sites in the region, such as pipeline telemetry shelters, communication rooms and small solar-powered stations, run a 48 V battery bank because it carries load with lower current than a 24 V system. The 5.4 W coil then draws about 0.11 A, which is modest enough for a small battery charger to carry along with the other loads.

On a 48 V coil the window of 0.7 to 1.25 Uc is about 33.6 to 60 V, and the drop-out band of 0.1 to 0.25 Uc is about 4.8 to 12 V. A float-charged 48 V bank sits comfortably inside the operating band, and on discharge the relay keeps working until the bank is nearly flat, which is usually what an alarm and trip circuit needs. Keep a diode or suppressor across the coil, because the stored energy of a DC coil at this voltage can stress the contact that switches it.

The datasheet gives operating times of 53 to 72 ms coil energisation and NO closing, 16 to 24 ms coil de-energisation and NO opening, 47 to 63 ms coil energisation and NC opening, 15 to 25 ms coil de-energisation and NC closing. The DC coil closes in 53 to 72 ms and opens in 16 to 24 ms, with a time constant of 28 ms, which is slower than an AC coil and should be kept in mind in tight timing circuits.

Installation and maintenance of the CAD32ED

Fit the relay in an enclosure with the front face reachable for inspection: the datasheet quotes IP2X at the front face, which protects against finger contact but not against dust. The weight of 0.58 kg is modest, so the relay is held securely by its rail clip, but plate mounting is preferable on machines with strong vibration. The datasheet lists vibration resistance of 2 Gn open and 4 Gn closed (5 to 300 Hz) and shock resistance of 10 Gn open and 15 Gn closed for 11 ms.

For spares planning, the CAD32ED is a good candidate for a stocked spare because it is physically identical to its siblings and the coil is the only part that differs. Mark the coil voltage clearly on the terminal block door or on the panel diagram, test it after any control-supply change, and keep a record of the coil code. The datasheet gives an 18-month warranty from the manufacturer, which applies to the product as supplied by its own channel.

Typical applications for the CAD32ED in the region

In Oman and the GCC a low-voltage DC coil is most often found in packaged skids, compressor and generator control panels, fire-and-gas interface cabinets and remote telemetry shelters, where a 12, 24 or 48 V battery-backed supply keeps the controls alive through a mains failure. In these cabinets the relay repeats a PLC or safety-system signal to field circuits, and the five poles save space compared with a bank of small plug-in relays.

For the CAD32ED, that means three normally open and two normally closed contacts from one 48 V DC command, sitting next to LC1D contactors of the same TeSys D family on the same rail.

Checks before ordering the CAD32ED

• Coil: 48 V DC, confirmed from the supply drawing or the nameplate of the relay being replaced.
• Contacts: three normally open and two normally closed contacts, matched to the interlock and signalling circuits.
• Supply sizing: about 112 mA continuously, because the datasheet gives the same power for inrush and hold-in (derived figure).
• Window: operates within 33.6 to 60 V (0.7 to 1.25 Uc) and releases at 4.8 to 12 V (0.1 to 0.25 Uc).
• Contact load of the CAD32ED: 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.

Related references to the CAD32ED

The CAD32ED 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 CAD32 references we are asked for most.

If the supply is not in the table, ask us; the CAD50 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.

What to include when you request a quote for the CAD32ED

• Delivery location in Oman or the GCC and the date required
• Panel or machine the relay must fit, and whether it is a spare, a replacement or a new installation
• The load or circuit each contact will switch (voltage, current, signal level)
• The coil voltage and type seen on the supply drawing or on the old relay nameplate
• Full reference CAD32ED and the quantity

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.