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Leipole Electric

Single-phase control transformer

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Overview

Compact single-phase control transformers, high-efficiency conversion, widely applicable.

  • Single-phase power supply application: suitable for single-phase power input equipment.
  • High-efficiency conversion: reduces losses and improves economy.
  • Compact design: saves installation space and adapts to a variety of installation environments.

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Key advantages

  • Ultra-Low No-Load Losses via Amorphous Core
    Amorphous-metal laminations reduce no-load (iron) losses by up to 60% compared to CRGO cores, delivering significant energy savings in lightly loaded or continuously energized applications.
  • Vacuum Pressure Impregnation (VPI) for Superior Insulation
    VPI-treated windings provide complete void-free resin encapsulation, enhancing dielectric strength, moisture resistance, and extending service life in high-humidity or corrosive environments.
  • Custom Tap-Changers for Precise Voltage Regulation
    On-load and off-load tap-changer options let you fine-tune secondary voltage in ±2.5 % steps without interruption, maintaining optimal output for sensitive loads like lighting, instrumentation, or UPS systems.
  • High Inrush Current Mitigation Designs
    Special “split-core” and interleaved winding topologies limit magnetizing inrush currents at energization, preventing nuisance tripping of upstream breakers and reducing mechanical stress on coils.
  • Low-Noise Acoustic Engineering
    Magnetic flux dispersion techniques and vibration-damping mounting brackets quiet core hum to below 25 dB(A), an essential feature in commercial, medical, or residential settings.
  • Embedded Thermal Protection & Diagnostics
    Built-in thermal sensors at hot-spot winding locations feed to remote monitoring systems, allowing real-time overload detection and predictive maintenance alerts before insulation degradation occurs.
  • Compact High-Flux Density Construction
    Optimized core stacking and high-grade silicon steel yield a 20–30 % smaller envelope compared to legacy designs, freeing panel or floor space in OEM machinery and electrical rooms.
  • Enhanced EMI/RFI Suppression
    Integrated electrostatic shields and line-filtering windings attenuate high-frequency noise and transient spikes, safeguarding downstream electronics and communication equipment.
  • Corrosion-Resistant Finishes & Enclosures
    Powder-coated steel or stainless-steel housings, plus class-H varnish on coils, ensure durability in outdoor, marine, or chemical-process environments without sacrificing thermal performance.
  • Eco-Friendly Dielectric Fluids
    In oil-cooled variants, biodegradable ester fluids replace mineral oil, offering a 30 °C higher flash point, improved fire safety, and reduced environmental impact in case of leaks.

Models & specifications

JBK 2 transformer

JBK2 Series: A cost-effective solution for basic control circuit applications. providing dependable performance with minimal maintenance requirements.

wdt_ID wdt_created_by wdt_created_at wdt_last_edited_by wdt_last_edited_at Model L (mm) W (mm) H (mm) A (mm) B (mm) KF F
1 Kiva 09/07/2025 05:20 AM Kiva 09/07/2025 05:20 AM JBK2-63VA 84 94 92 64 ± 0.2 62 ± 0.2 46 15
2 Kiva 09/07/2025 05:20 AM Kiva 09/07/2025 05:20 AM JBK2-100VA 96 105 105 84 ± 0.2 87 ± 0.2 58 15
3 Kiva 09/07/2025 05:20 AM Kiva 09/07/2025 05:20 AM JBK2-160VA 96 110 105 84 ± 0.2 85 ± 0.2 58 15
4 Kiva 09/07/2025 05:20 AM Kiva 09/07/2025 05:20 AM JBK2-250VA 120 100 122 90 ± 0.2 85 ± 0.2 58 15
5 Kiva 09/07/2025 05:20 AM Kiva 09/07/2025 05:20 AM JBK2-400VA 120 115 122 90 ± 0.2 96 ± 0.2 7 2
6 Kiva 09/07/2025 05:20 AM Kiva 09/07/2025 05:20 AM JBK2-500VA 150 110 145 122 ± 0.2 90 ± 0.2 7 2
7 Kiva 09/07/2025 05:20 AM Kiva 09/07/2025 05:20 AM JBK2-630VA 150 128 145 122 ± 0.2 105 ± 0.2 7 2
8 Kiva 09/07/2025 05:20 AM Kiva 09/07/2025 05:20 AM JBK2-800VA 168 125 155 138 ± 0.2 105 ± 0.2 9 2
9 Kiva 09/07/2025 05:20 AM Kiva 09/07/2025 05:20 AM JBK2-1KVA 168 125 155 138 ± 0.2 105 ± 0.2 9 2
10 Kiva 09/07/2025 05:20 AM Kiva 09/07/2025 05:20 AM JBK2-1.6KVA 168 138 155 138 ± 0.3 116 ± 0.5 10 3
Model L (mm) W (mm) H (mm) A (mm) B (mm) KF F

JBK3 Control transformers

ldeal for standard applications, offering reliable power and durability for general industrial use.

wdt_ID wdt_created_by wdt_created_at wdt_last_edited_by wdt_last_edited_at Model B max D max E max A C Hole diameter K F max
1 Kiva 09/07/2025 05:27 AM Kiva 09/07/2025 05:27 AM JBK3-40、63 78 72 89 56±0.4 51±2 48 2
2 Kiva 09/07/2025 05:27 AM Kiva 09/07/2025 05:27 AM JBK3-100 85 85 94 64±0.4 66±2 48 2
3 Kiva 09/07/2025 05:27 AM Kiva 09/07/2025 05:27 AM JBK3-160 96 91 109 84±0.4 73±2 58 2
4 Kiva 09/07/2025 05:27 AM Kiva 09/07/2025 05:27 AM JBK3-250 95 105 109 84±0.4 87±2 58 2
5 Kiva 09/07/2025 05:27 AM Kiva 09/07/2025 05:27 AM JBK3-400 120 109 123 90±0.4 90±2 7 25
6 Kiva 09/07/2025 05:27 AM Kiva 09/07/2025 05:27 AM JBK3-630 150 112 150 122±0.5 77±2 6 25
7 Kiva 09/07/2025 05:27 AM Kiva 09/07/2025 05:27 AM JBK3-1000 160 195 151 126±2 152±2 7 3
8 Kiva 09/07/2025 05:27 AM Kiva 09/07/2025 05:27 AM JBK3-1600 184 220 163 140±2 176±2 7 3
9 Kiva 09/07/2025 05:27 AM Kiva 09/07/2025 05:27 AM JBK3-2500 200 250 171 172±2 200±2 7 4
Model B max D max E max A C Hole diameter K F max

JSG 3 Control transformers

JBK5 Series: Desiqned for advanced industrial environments, with improved aesthetics, safety features, and voltage stability for more demanding conditions.

wdt_ID wdt_created_by wdt_created_at wdt_last_edited_by wdt_last_edited_at Model Order number B max D max E max A C Hole diameter K F max Remarks
1 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK5-40. 63 4011-01-01 78 72 90 56±0.15 46±0.125 46 15
2 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK5-100 4011-01-03 84 75 96 64±0.15 62±0.15 46 15
3 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK5-160 4011-01-04 96 92 105 84±0.175 73.5±0.15 55 15
4 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK5-250 4011-01-05 96 100 104 84±0.175 85±0.175 58 15
5 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK5-400 4011-01-06 120 100 122 90±0.175 8510.175 58 2
6 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK5-500 120 110 122 90±0.175 96±0.175 58 2
7 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK5-630 4011-01-07 150 no 140 122±0.2 9010.175 7 2
8 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK5-800 4011-01-08 150 128 142 122±0.2 10510.2 7 2
9 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK5-1000 150 190 142 126±0.2 15210.2 7 3 Horizontal
10 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK5-1000 168 125 155 138±0.2 10510.2 9 2 Vertical
Model Order number B max D max E max A C Hole diameter K F max Remarks

JBK6 Control transformers

JBK6 Series: Built for harsh environments, featuring corrosion resistanceand protection against extreme conditions like humidity, coastal exposureor desert climates.

wdt_ID wdt_created_by wdt_created_at wdt_last_edited_by wdt_last_edited_at Model Order number B max D max E max A C Hole diameter K F max Remarks
2 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK6-40. 63 4013.001/2 78 72 90 56±0.15 46±0.125 4.6 1.5
3 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JJBK6-100 4013.003 85 75 96 64±0.15 62±0.15 4.6 1.5
4 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK6-160 4013.004 96 92 105 84±0.175 73.5±0.15 5.5 1.5
5 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK6-250 4013.005 96 100 104 84±0.175 85±0.175 5.8 1.5
6 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK6-400 4013.006 120 100 122 90±0.175 85±0.175 5.8 2
7 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK6-500 4013.007 120 110 122 90±0.175 96±0.175 5.8 2
8 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK6-630 4013.008 150 110 140 122±0.2 90±0.175 7 2
9 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK6-800 4013.009 150 128 142 122±0.2 105±0.2 7 2
10 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK6-1000 4013.01 150 190 142 126±0.2 152±0.2 7 3 Horizontal
11 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK6-1000 4013.011 168 125 155 138±0.2 105±0.2 9 2 Vertical
Model Order number B max D max E max A C Hole diameter K F max Remarks
JBK7 Control transformers

JBK7 Series: The premium option for critical and high-performance applications, delivering low energy loss, high efficiency, and superiorreliabilityin extreme temperatures.

wdt_ID wdt_created_by wdt_created_at wdt_last_edited_by wdt_last_edited_at Model Order number B max D max E max A C Hole diameter K F max Remarks
2 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK7-40. 63 4014.001/2 78 72 90 56±0.5 46±0.5 4.6 1.5
3 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK7-100 4014.003 84 75 96 64±0.5 62±0.5 4.6 1.5
4 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK7-160 4014.004 96 92 105 84±0.5 73.5±0.5 5.5 1.5
5 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK7-250 4014.005 96 100 104 84±0.5 85±0.5 5.8 1.5
6 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK7-300 4014.006 120 112 105 84±0.5 85±0.5 5.8 2
7 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK7-400 4014.007 150 100 122 90±0.5 85±0.5 5.8 2
8 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK7-630 4014.008 150 110 140 122±0.5 90±0.5 7 2
9 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK7-800 4014.009 150 128 142 122±0.5 105±0.5 7 2
10 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK7-1000 4014.01 150 205 142 126±0.2 152±0.2 7x12 3 Horizontal
11 Kiva 09/07/2025 07:29 AM Kiva 09/07/2025 07:29 AM JBK7-1000 4014.011 168 138 155 138±0.5 105±0.5 9x15 2 Vertical
Model Order number B max D max E max A C Hole diameter K F max Remarks

All 2 model pages

Applications

  • Residential Power Supply – Step down utility voltage (240 V/120 V) for safe, reliable home appliances and lighting circuits.
  • Lighting & Signage – Provide low-voltage power (e.g., 24 V, 12 V) for LED signage, landscape lighting, and architectural fixtures.
  • HVAC Control Circuits – Feed thermostats, valves, and control relays with stable 24 V or 120 V supplies in heating, ventilation, and air-conditioning systems.
  • Industrial Control Panels – Supply safe low-voltage power to PLCs, timers, and control relays in small-to-mid-size machine enclosures.
  • Telecom & Data Equipment – Isolate and regulate 48 V or 24 V DC station power for routers, switches, and remote terminal units.
  • Solar Power Inverters – Step up or down panel-mounted DC inverters to match grid or battery-bank voltages in small photovoltaic systems.
  • UPS & Battery Chargers – Provide isolated AC input for battery-charger circuits and uninterruptible power supplies in critical backup applications.
  • Medical & Laboratory Instruments – Deliver isolated, low-noise power for sensitive diagnostic, imaging, and analytical equipment.
  • EV Charger Control – Step down line voltage to control electronics (PLC, metering, display) within single-phase electric vehicle charging stations.
  • Audio & Broadcast Systems – Isolate and regulate voltage for studio consoles, amplifiers, and rack-mount broadcast gear to prevent ground loops and noise.

Basic knowledge

1. Core Lamination & Magnetic Flux Management

  • Grain-oriented silicon steel with ultra-thin (≤0.23 mm) laminations slashes hysteresis losses. Cheaper units use thicker, non-oriented laminations, generating excess heat under light loads and accelerating insulation ageing.

2. Inrush Current Mitigation

  • Split-winding topologies or auxiliary “magnetizing” windings limit energization inrush to ≤5× rated current. Without this, breakers trip and core stress “buzz” develops, especially in larger kVA units.

3. Insulation & Varnish Techniques

  • Vacuum pressure impregnation (VPI) creates a void-free resin encapsulation around coils, preventing moisture ingress and corona discharge in high-humidity or fluctuating-voltage environments.

4. Thermal Hot-Spot Monitoring

  • Embedding fiber-optic temperature probes at the coil’s hottest turn gives real-time hotspot data. Traditional external RTDs lag actual winding temperature by 10–15 °C, risking unseen insulation breakdown.

5. Acoustic & Mechanical Vibration Control

  • Acoustic dampening laminations and spring-isolated feet eliminate core-coil microphonic noise in office or residential installs. Rigid mounting in mobile or pump-room panels leads to fatigue cracks over time.

6. Tap-Changer Accuracy

  • On-load tap changers (OLTC) with ±1% step accuracy maintain precise secondary voltage under varying loads. Off-load units spur downtime for adjustments, unacceptable in continuous processes.

7. Environmental & Chemical Resistance

  • Class H varnish coatings resist chemical fumes in manufacturing plants, while LSZH (Low Smoke Zero Halogen) materials prevent toxic gas release in enclosed or public-space installations.

8. Lifecycle & Predictive Maintenance

  • Annual partial-discharge testing detects microscopic voids in insulation before full failure. Infrared thermography pinpoints loose connections or early hotspot formation, extending service life by years.

Frequently asked questions

When do I need a 240 V to 120 V step-down transformer?

Use it when you must power 120 V appliances from a 240 V supply—common in international machinery retrofits and specialty HVAC equipment.

What makes a 1 kVA transformer ideal for home applications?

A 1 kVA unit safely handles typical household loads—lighting, small appliances, and electronics—without over-specifying and wasting energy.

Why choose a toroidal transformer for low-noise requirements?

Toroidal cores emit < 25 dB(A) hum thanks to uniform winding and low magnetic flux leakage—perfect for studios, labs, and audio equipment.

What are the benefits of dry-type transformers in industrial settings?

Dry-type units eliminate oil-related fire risk, require no leak-prone maintenance, and withstand high ambient temperatures with Class H insulation.

How does a transformer for HVAC control differ from general-purpose types?

HVAC control transformers provide precise low-voltage outputs (often 24 V) and handle high inrush currents from motor starters and solenoid valves.

Product inquiry

Related products

Selection & support

Selecting a LEIPOLE single-phase control transformer

Match the rating, voltages and protection to the control circuit.

Which single-phase control transformers does LEIPOLE supply?

LEIPOLE supplies five JBK series covering 40 VA to 60 kVA: JBK2 from 63 VA to 20 kVA, JBK3 from 40 VA to 2500 VA for machine tools, JBK5 from 40 VA to 60 kVA, JBK6 from 40 VA to 2500 VA with short-circuit and heat protection, and JBK7 from 40 VA to 2500 VA for low loss. They step the supply down to the control voltage of contactors, relays and lamps.

Compare three-phase transformers

What do I need to specify when ordering a control transformer in Singapore?

Give the series and rating in VA or kVA, the primary (input) voltage, the secondary (output) voltage or voltages, the frequency and the quantity. Size the rating above the total power of the coils, lamps and devices fed, with margin for contactors that pull in together.

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