Schneider Electric LADS2 TeSys D On-Delay Timer Block 1-30 s

LADS2: on-delay timer block listed for star-delta starters

The LADS2 is a Schneider Electric TeSys D time delay auxiliary contact block with an on-delay function and a range of 1 to 30 seconds, and its datasheet notes the application as star delta starter. It carries one normally open and one normally closed timed contact. Seven Star LLC supplies the LADS2 in Oman and the GCC as an independent supplier based in Muscat.

Among the five timers here, the LADS2 is the only one whose datasheet names a device application. It has the same on-delay range as the LADT2, so the star-delta mention is the practical difference between the two references.

Technical specifications of the LADS2

The star-delta job of the LADS2

A star-delta starter starts a motor with its windings in star to limit starting current, then changes over to delta after a set time. The timer must hold the star contactor in for the run-up and then drop it. A range of 1 to 30 seconds covers the run-up of most pumps and fans of moderate size.

The on-delay function means the contacts change state after the set time following energisation of the contactor, which is what the changeover needs. Set the time to the actual run-up of the machine, and not to a guess, by measuring the current or speed during the first starts.

LADS2 selection notes

• On delay, 1 to 30 s; contacts 1 NO + 1 NC.
• Application noted: star delta starter.
• Compare with the LADT2, which has the same range without the star-delta note.
• Compare with the LADT4 if the run-up exceeds 30 s.
• Contactor compatibility as in the datasheet.

Ratings and mounting of the LADS2

The block fits on the front of TeSys D and TeSys Deca contactors and CAD relays, and on TeSys F LC1F and CR1F, which is the range compatibility line in the datasheet. It has one normally open and one normally closed time-delayed contact and measures 48 mm high, 44 mm wide and 61 mm deep. Rated operational voltage is 690 V AC at 25 to 400 Hz, thermal current is 10 A at 60 °C, rated current is 6 A at 120 V AC-15 and 1.04 A at 690 V AC-15, and the making capacity is 140 A AC. Mechanical durability is 5 Mcycles, the minimum switching level is 5 mA at 17 V, and the protection is IP20. The ambient air temperature range is -40 to 70 °C and the altitude limit is 3000 m.

The datasheet adds a short-time rating of 100 A for 1 s, 120 A for 500 ms and 140 A for 100 ms at 60 °C.

Timer block family: the LADS2 against its siblings

The five timer blocks below share the housing and contact ratings and differ in function and range.

Setting up a star-delta timer with the LADS2

Fit the block on the star contactor, wire the changeover chain according to your starter diagram, and set the delay to the run-up time. Terminals take 1 to 2.5 mm² flexible, tightened at 1.7 N.m.

Observe the first start with a clamp meter. The current peak at changeover tells whether the time is too short, and a long star period tells it is too long.

LADS2 in Oman and the GCC

Star-delta starting is widely used for pumps, compressors and fans of tens of kilowatts in water, HVAC and industrial plants, where a direct-on-line start would stress the supply. The LADS2 is the timer that those panels use.

Supply networks in remote sites can be weak, so correct changeover timing is more than a nicety.

Information to send with an RFQ for the LADS2

• Full reference and quantity required
• Contactor model the block mounts on
• Delay function (on or off) and time range needed
• Control voltage and load of the timed contacts
• Delivery location and timing

Documents and quotation

A datasheet for the LADS2 is attached on this page. It carries the electrical, mechanical and environmental data summarised above, so the figures can be checked against your drawings.

Send 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.