single phase control transformer
Bk100va-5kva Single Phase Isolation Control Power Transformer
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single phase control transformer
Bk100va-5kva Single Phase Isolation Control Power Transformer
control transformer supplier
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25kva Single Phase Pole Mounted Distribution Transformer 13.2KV To 240V
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SG 10kva-1000kva Three Phase Dry Type Isolation Step Up Transformer
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Bk 100va-5kva Single Phase Isolation Control Power Transformer

The BK series single-phase isolation control power transformer (commonly called a BK transformer) delivers stable, isolated control voltages for industrial and commercial equipment. Available from 100 VA to 5 kVA, the unit uses a thyristor (SCR) control module with feedback to provide precise closed-loop voltage regulation even when the input supply fluctuates.

This control transformer is built to international safety and efficiency standards and is perfect for CNC machines, PLCs, automation panels, lighting circuits, and other precision systems that need a stable control supply.

SKU: BK Category: , , ,
Description

Key features & benefits

  • Capacity range: 100 VA – 5 kVA (wide range to fit small control panels up to medium machinery).
  • Flexible input options: Custom input voltages available — typical choices: 360 V / 380 V / 415 V / 440 V (single-phase or as required).
  • Customizable outputs: Standard outputs include 12 V, 24 V, 36 V, 48 V, 60 V, 120 V, 220 V (other voltages available on request).
  • Thyristor (SCR) control module: Smooth, fast regulation with closed-loop feedback to keep the output steady under varying load or supply.
  • High efficiency: Typical efficiency up to 98% depending on model and load.
  • Strong insulation & safety: Insulation resistance ≥ 50 MΩ; dielectric withstand test 3000 V for 1 minute (no breakdown).
  • Durable construction: Silicon-steel laminations in the core for low loss and long service life.
  • Easy wiring options: Jumper/linkable terminals for multi-tap or different voltage configurations (makes installation flexible).

Model Meaning

Model BK □
B transformer
K control
□ rated capacity

Technical Parameters

Model NO. BK
Capacity 100VA   150VA   200VA      250VA     300VA     400VA      500VA      700VA   800VA   1KVA   1.2KVA   1.5KVA   2KVA   2.5KVA     3KVA   4KVA   5KVA
Input voltage Two phase 440V/415V/380V/360V
Output voltage Customizable two-phase 440V/12V/24V/36V/48V/60V/120V/220V
Frequency 50Hz/60Hz
Work efficiency ≥98%
Insulation resistance ≥50MΩ
Waveform distortion No additional waveform distortion
Overload capacity Two times the rated current for one minute
Electrical strength Industrial frequency sinusoidal voltage 3000V for onr minute without breakdown phenomenon
Ambient temperature -15°C~+ 40°C

How it works (simple)

Input feeds the transformer core.
The SCR control module adjusts conduction angle to regulate output voltage.
A feedback circuit constantly monitors output vs. setpoint and corrects the SCR firing to keep voltage stable.
This closed-loop approach gives smooth regulation and protects sensitive control devices from surges or sags.

Specifications

MODEL Overall size(mm) Installation size Aperture(K*J)
B D E A C
BK-100VA 98 85 108 84 65 5*8
BK-150VA 105 86 110 76 77 5*8
BK-200VA 105 105 115 85 87 8*11
BK-250VA 105 115 110 85 95 8*11
BK-300VA 115 110 115 90 90 8*11
BK-400VA 135 125 140 110 97 8*13
BK-500VA 135 130 140 110 103 8*13
BK-600VA 152 110 150 120 90 8*13
BK-700VA 152 110 150 120 90 8*13
BK-800VA 152 125 150 120 105 8*13
BK-1KVA 152 142 165 120 120 8*13
BK-1.5KVA 175 170 195 130 120 8.5*17
BK-2KVA 205 215 230 170 130 8*11
BK-2.5KVA 205 225 230 170 140 8*11
BK-3KVA 205 240 230 170 150 8*11
BK-4KVA 235 265 260 195 175 8*11
BK-5KVA 235 280 260 195 190 8*11

Control transformer dimensions

Control-transformer-dimensions

Typical Applications

Control circuits for CNC machines and motor drives.
Industrial automation: PLCs, relays, contactors.
Lighting & HVAC control circuits needing isolation.
Laboratory and test equipment requiring precise, low-distortion control power.
Any application needing a single-phase transformer with precise regulated output or electrical isolation.

Why choose ZHENGXI BK transformers

ISO-certified manufacturing and global quality control.
Custom engineering: we adapt voltages, mounting, enclosures, and frequency (50/60 Hz) to your needs.
Export ready: CE & RoHS compliance for international markets.
Proven experience: decades supplying OEM/ODM solutions to industrial clients worldwide.

FAQs

Q1: What makes a BK transformer different from a regular single-phase transformer?
A: The BK is a control/isolation transformer that includes a thyristor (SCR) module and feedback for closed-loop voltage regulation. A standard single-phase transformer only steps voltage up or down and does not actively regulate output under changing input conditions.

Q2: How do I choose the right size (VA/kVA)?
A: Add up the control circuit load in VA, then add 20–25% margin for start-up or surge current. If unsure, send your load list to our engineers and we’ll recommend the right BK transformer size.

Q3: Can you customize voltages and enclosures for export?
A: Yes. We provide custom input/output voltages, 50/60 Hz options, and export-grade enclosures. ZHENGXI supports CE and RoHS requirements.

Need a quote or help sizing the right BK transformer or control transformer for your equipment? Contact our engineers today — we offer fast custom solutions and technical support.

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