Schneider Electric CAD32BD TeSys D Relay 3NO+2NC 24V DC

What the CAD32BD is and how its code is built

This page covers the CAD32BD, a TeSys D control relay from Schneider Electric with three normally open and two normally closed contacts and a 24 V DC coil. It belongs to the CAD range, which uses the same compact housing as the TeSys D contactors but is built for control duty. Seven Star LLC is an independent supplier in Muscat and supplies the CAD32BD in Oman and the GCC.

Part-number logic: the family is TeSys D control relay (CAD), the contact block is three normally open and two normally closed contacts, and the suffix BD corresponds to the 24 V DC coil. That is exactly what the manufacturer’s description says for this reference, so a quote request should always quote the complete CAD32BD and never just the family prefix.

Choosing the supply for the CAD32BD coil

The coil is the one part that distinguishes the CAD32BD from its siblings, so it deserves the closest reading.

The 24 V DC coil is the everyday choice for control panels that already carry a 24 V supply for PLC inputs, sensors and indicator lamps. The datasheet lists 5.4 W for this standard-consumption coil, which is about 0.23 A when the relay is held in. That is more than a typical transistor output channel will deliver on its own, so the coil is usually driven through an interposing element or from a relay or output rated for the current.

The operational window of 0.7 to 1.25 Uc corresponds to roughly 16.8 to 30 V on this coil, which covers the ripple and sag of an ordinary unregulated or lightly loaded 24 V supply, and the drop-out band of 0.1 to 0.25 Uc, about 2.4 to 6 V, means the relay releases cleanly when the supply is removed. Choose the standard coil when the supply is generous and fast operation matters; the low-consumption alternative with suffix BL trades speed and power for a smaller load on the supply.

Sizing the coil circuit is straightforward with the datasheet figures. The listed power is 5.4 W for inrush and for hold-in; at 24 V that is roughly 225 mA both on pull-in and held in. The coil operates within 16.8 to 30 V (0.7 to 1.25 Uc) and releases within 2.4 to 6 V (0.1 to 0.25 Uc). As these currents are derived rather than quoted, leave margin in the supply and check them against the nameplate of the exact relay you receive.

CAD32BD specification table

Pre-order checklist for the CAD32BD

• Coil: 24 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 225 mA continuously, because the datasheet gives the same power for inrush and hold-in (derived figure).
• Window: operates within 16.8 to 30 V (0.7 to 1.25 Uc) and releases at 2.4 to 6 V (0.1 to 0.25 Uc).
• Contact load of the CAD32BD: 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.

Where the contacts of the CAD32BD earn their keep

The 3 NO + 2 NC configuration is the most flexible arrangement for a control relay, because the normally closed pair lets one device take part in interlocking and fault-reset circuits as well as repeating a signal. The datasheet lists a non-overlap time of 1.5 ms on energisation and 1.5 ms on de-energisation between the normally closed and normally open contacts, so that the two groups do not conduct at the same time during a transition.

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.

Sibling references: CAD32BD and the other CAD32 relays

The CAD32BD 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.

Applications of the CAD32BD in Oman and the GCC

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.

Heat and dust shape the choice. A cabinet in direct sun on a desert site can run far above the 40 °C that many catalogues assume, so look at the 60 °C operating limit and the derating up to 70 °C given in the datasheet, and keep the relay out of the hottest zone near the power supply and any drive.

For the CAD32BD, that means three normally open and two normally closed contacts from one 24 V DC command, sitting next to LC1D contactors of the same TeSys D family on the same rail.

Fitting the CAD32BD in a panel

Mount the CAD32BD 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.

RFQ details for the CAD32BD

• Full reference CAD32BD 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.