Schneider 3-pole main contacts LC1D38BD

Schneider TeSys Deca series, 3-ขั้วสัมผัสหลัก, 24คอยล์วีดีซี. Designed for motor start/stop, HVAC and automation control cabinets. Built-in 1NO+1NC auxiliary contacts.

✅ Model Code Definition

แอลซี1: คอนแทคเตอร์มาตรฐาน

ดี: เทซิส ดี (เดคา) ชุด

38: Rated operational current 38A @ AC-3, 400วี

บีดี: 24ขดลวด วีดีซี (integrated coil surge suppression)

📌 Key Electrical Specifications

🛠️ Typical Applications

Direct-on-line, star-delta and forward/reverse control of 3-phase asynchronous motors

ระบบปรับอากาศ, ปั๊มน้ำ, แฟน ๆ, เครื่องอัดอากาศ

อุปกรณ์อัตโนมัติ, packaging machinery and production line control cabinets

Direct coil drive by PLC 24VDC digital outputs (no intermediate relay required)

🧩 Compatible Accessories

รีเลย์โอเวอร์โหลดความร้อน: ซีรีส์ LRD (LRD35…), snap-fit directly below the contactor

Auxiliary contact block: LA1DN (for extra NO/NC contacts)

โมดูลเชื่อมต่อทางกล: LA9D4001 (for forward/reverse interlock)

ปราบปรามไฟกระชาก: Integrated inside coil, no external component needed

🔁 Alternative & Compatible Selection

1. AC coil variants within the same series: LC1D38M7 (220VAC), LC1D38B7 (24VAC)
2. ทางเลือกภายในประเทศ: CJX2-3811 DC24V (note differences in dimension, terminals and mechanical life)

⚠️สำคัญ: BD = 24VDC, B7 = 24VAC. Coils are NOT interchangeable.

📋 Certifications & มาตรฐาน

ไออีซี 60947-1/-2/-4-1, ซีซีซี, คิวลัส. Complies with IEC60335-1 flame retardant standard and A2L refrigerant safety certification for HVAC.

🧪 Second-hand Inspection Checklist

1. ม้วน: Continuity check on A1/A2. Apply 24VDC; armature pulls in without noise or overheating.
2. ผู้ติดต่อหลัก: L1/L2/L3 ↔ T1/T2/T3. Conductive when closed, high resistance when open; inspect contact erosion.
3. ผู้ติดต่อเสริม: 13-14(เลขที่), 21-22(เอ็นซี). Switch synchronously with main contacts.
4. เครื่องกล: ไม่ติด; housing free of cracks or carbon blackening.

HS Code Reference

8536410000 (Electromagnetic contactor, voltage ≤60V)

Typical Engineering Application Cases for LC1D38BD

Core advantages: คอยล์ DC24V, direct PLC drive without intermediate relay; built-in surge suppression and certified mirror NC contact; 18.5kW max 3-phase motor @ AC-3, 50A for AC-1 resistive loads

กรณี 1: Chilled water pump DOL start for HVAC BMS (ระบบอัตโนมัติในอาคาร)

โหลด: 15kW 3-phase chilled water pump, 380วี, motor rated current ≈28A

รูปแบบการควบคุม: บมจ (ซีเมนส์ / Schneider M241) DO directly drives LC1D38BD 24VDC coil

วงจรหลัก: 3P circuit breaker → LC1D38BD → LRD35 thermal overload relay → pump motor

ตรรกะการควบคุม: BMS outputs 24VDC based on water temperature/pressure differential to energize contactor and start pump. Built-in 1NO auxiliary contact feeds running status back to PLC; built-in mirror NC contact for fault acquisition.

เหตุผลในการคัดเลือก: DC coil provides strong anti-interference. BMS cabinets commonly adopt DC24V control. Wide temperature range -5~+60℃ suits high-temperature equipment rooms. 45ตัวเครื่องแคบ มม. ช่วยประหยัดพื้นที่ตู้.

เครื่องประดับ: LRD35 thermal relay (28~36A), การติดตั้งราง DIN.

กรณี 2: Air compressor motor control (OEM machinery manufacturer)

โหลด: 18.5kW screw air compressor main motor, 400วี

รูปแบบการควบคุม: PLC directly drives LC1D38BD with pressure switch interlock for shutdown

เซอร์กิต: Circuit breaker → LC1D38BD → LRD thermal relay → air compressor motor

คุณสมบัติ: การสตาร์ท-หยุดบ่อยครั้ง (สูงสุด 3600 รอบ/ชั่วโมง). DC coil pulls in stably without AC hum. Built-in coil surge suppression protects PLC output points against back EMF.

บันทึก: AC-3 operation reaches the 38A rating limit. Derating evaluation is recommended for heavy-duty frequent cycling.

กรณี 3: Water treatment — duty/standby mutual interlock control cabinet for sewage lift pumps

โหลด: Two 15kW sewage pumps, duty-standby auto-switching by liquid level

การกำหนดค่า: 2 × LC1D38BD + LA9D4001 mechanical interlock module

ตรรกะ: Pump starts on high liquid level. If main pump trips (thermal relay fault), PLC automatically switches to standby pump. Mechanical interlock prevents simultaneous closure and short circuit.

Safety feature: Built-in mirror NC contact for safety loop and fault diagnosis, meeting water treatment control cabinet safety specifications.

แอปพลิเคชัน: Municipal sewage, factory circulating water, rainwater lift pumping stations.

กรณี 4: Forward/reverse circuit for conveyor motors in packaging machinery / สายการผลิต

โหลด: 11~15kW belt conveyor motor requiring forward and reverse rotation

การกำหนดค่า: 2 × LC1D38BD (KM1 forward, KM2 reverse) + LA9D4001 mechanical interlock

ควบคุม: PLC 24VDC digital outputs drive each contactor coil separately. อินเตอร์ล็อคไฟฟ้า (using built-in NC auxiliary contacts) plus mechanical interlock provides double protection to prevent power short circuit.

ข้อได้เปรียบ: DC coil has better EMI immunity than AC coils in workshops dense with inverters and sensors, reducing accidental pull-in faults.

กรณี 5: Star-delta reduced voltage starting for 18.5kW dust extraction fan

โหลด: 18.5kW dust removal fan with high inrush current, star-delta starting adopted

การกำหนดค่า: 3 × LC1D38BD, serving as main contactor, star contactor and delta contactor respectively

ตรรกะ: PLC outputs 24VDC sequential control; star reduced-voltage start first, then time-delayed switch to delta full-voltage operation. Built-in contactor auxiliary contacts provide status feedback and electrical interlock.

บันทึก: High inrush current occurs at delta switching in star-delta circuits; contact life must be reviewed.

กรณี 6: AC-1 resistive load: Industrial heating module control

โหลด: 3-phase heating elements, total resistive load ≤33kW (AC-1 50A @400V)

คุณสมบัติ: Resistive load has no starting inrush current. AC-1 rated 50A capacity higher than motor duty. PLC 24V DO directly controls heating circuit on/off.

แอปพลิเคชัน: Ovens, constant temperature units, process heating equipment.

กรณี 7: Cleanroom air handling unit for medical facilities (medical HVAC)

โหลด: 15kW supply air fan for operating room clean air conditioning

คุณสมบัติ: Medical equipment demands high reliability and low EMI. LC1D38BD DC coil with built-in surge suppression, no electromagnetic noise from AC coils. Complies with IEC60335 HVAC safety standard, suitable for A2L refrigerant HVAC equipment, widely used in hospital BMS control cabinets.

การคัดเลือกทั่วไป & Construction Key Points (Valid for All Cases)

1. DC coil critical note: BD = 24VDC, MUST NOT be connected to AC24V. PLC output capacity must meet coil power consumption (~15VA).
2. ผู้ติดต่อเสริม: Built-in 1NO (running feedback) +1เอ็นซี (mirror safety contact, NOT for normal latching). Add LA1DN auxiliary contact block for more contacts.
3. การป้องกันการโอเวอร์โหลด: Must be fitted with LRD thermal overload relay, set per motor nameplate current and shall not exceed motor rated current.
4. Utilisation category distinction

เอซี-3 (normal motor start-stop): 38ก, max 18.5kW @400V

เอซี-1 (pure resistive heating): 50ก

เอซี-4 (วิ่งจ๊อกกิ้งบ่อยๆ, plug braking): จำเป็นต้องมีการลดอัตรา

Not Suitable Applications

Direct-on-line starting of 3-phase motors above 18.5kW (เอซี-3)

High-power capacitor switching (use dedicated LC1DxxKQ capacitor contactors)

พื้นที่อันตรายจากการระเบิด (explosion-proof series required)

LC1D38BD (TeSys D DC Coil) โครงร่าง & ขนาดการติดตั้ง

Without attached accessories (ผู้ติดต่อเสริม, รีเลย์ความร้อน, ลูกโซ่ทางกล), รุ่นคอยล์ DC

ขนาดเค้าร่าง (กว้าง × สูง × ลึก)

45 มม. × 85 มม. × 92 มม

ความกว้าง: 45มม (DIN rail module, 1 module unit)

ความสูง: 85มม

ความลึก: 92มม (from mounting backplate to front face)

Panel screw mounting holes (DC coil specific, round holes for M4)

Horizontal center distance between two holes: 35 มม

Vertical center distance between two holes: 70 มม

Screw size: ม4, two round holes (⚠️ AC coil LC1D38M7 uses slotted holes; mounting layout differs from BD DC version)

การติดตั้งราง

ใช้งานร่วมกับราง DIN มาตรฐาน 35 มม (TH35-7.5), clip-on installation, no drilling required.

Cabinet Layout Recommendations

1. Mounting LRD thermal relay at bottom: overall height increases; reserve adequate clearance.
2. Mounting LA1DN auxiliary contact block on top: extra depth and height required.
3. Multiple contactors side-by-side: 45ความกว้างมม, can be mounted tightly on rail without gap. Reserve heat dissipation gap for high-temperature environments.

Operating Principle of Schneider LC1D38BD Contactor

LC1D38BD is an electromagnetic contactor with DC coil (TeSys ซีรีส์ D). โดยพื้นฐานแล้ว, it is a remotely controlled electrical switch driven by 24VDC electromagnet, using low DC signal to switch high-power 3-phase main circuit.

1. โครงสร้างพื้นฐาน
2. Electromagnetic actuation section (Coil A1/A2): 24V DC excitation coil, fixed core, moving armature, สปริงกลับ
3. ผู้ติดต่อหลัก (power circuit L1/L2/L3 → T1/T2/T3): 3 pairs of normally-open main contacts, rated 38A AC-3, carrying high current for 3-phase motors / heating loads
4. ผู้ติดต่อเสริม (สัญญาณตอบรับ): Built-in 1NO (13-14)+1เอ็นซี (21-22) mirror auxiliary contacts for status feedback and electrical interlock
5. Arc chamber: Extinguishes electric arc when main contacts open, protecting contacts from rapid erosion

✅ Key feature for BD model: DC coil with integrated surge suppressor.

2. Full Operating Sequence

2.1 Coil Energized (Pull-in action)

Apply DC24V to A1 and A2 via PLC or external control circuit:

DC coil generates constant magnetic field, magnetizing fixed core, overcoming return spring force and pulling in moving armature.

Armature drives contact carrier synchronously:

3 pairs of main NO contacts close → 3-phase main circuit energized, motor/load powered on

Auxiliary contacts switch simultaneously: 13-14(เลขที่) ปิด; 21-22(เอ็นซี) เปิด

Characteristic of DC coil: constant current after pull-in, no vibration or hum from AC coils.

2.2 Coil De-energized (Drop-out action)

DC24V control signal removed:

Magnetic field of coil disappears, return spring pulls armature back.

All main contacts open, cutting high-current main circuit.

รีเซ็ตผู้ติดต่อเสริม: 13-14(เลขที่) เปิด; 21-22(เอ็นซี) restores closed state.

Built-in surge suppression absorbs back EMF generated at coil de-energization, protecting upstream PLC output points.

3. Core Differences Between DC Coil (บีดี) and Conventional AC Coil
4. คอยล์ไฟฟ้ากระแสสลับ: operates on alternating magnetic field, prone to vibration and hum; high inrush current; contact bounce under voltage fluctuation.
5. LC1D38BD DC24V coil:

Stable magnetic field, armature free of vibration, การทำงานที่เงียบ

Pull-in current ≈ holding current, การไหลเข้าต่ำ

Built-in freewheeling suppression, ideal for direct PLC DO drive

Disadvantage: Must never connect to AC supply; AC input burns coil immediately.

4. Typical Functions of Auxiliary Contacts

1เลขที่ (13-14): Running status feedback to PLC to detect contactor pull-in state

1เอ็นซี (21-22, mirror contact): วงจรความปลอดภัย, fault detection, electrical interlock (forward/reverse circuits)

⚠️ Mirror contact property: NC contact cannot close when main contacts are welded shut, complying with safety circuit requirements.

5. Mandatory Protection Logic for Engineering

The contactor only performs switching and has NO overload protection:

Fit LRD thermal overload relay in main circuit: on motor overload, thermal relay NC contact opens contactor coil circuit to cut motor power.

Circuit breaker installed upstream: fast short-circuit protection for main power supply.

One-sentence summary:

Apply DC24V to A1/A2; electromagnetic force actuates internal contacts to close high-power 3-phase main circuit. Remove 24V supply; spring resets and opens main circuit. Low-voltage 24V signal remotely switches high-power loads. Auxiliary contacts provide status feedback and safety interlock.