Bk Single Phase Isolation Control Transformer Manufacturer

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.

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)
MODEL	B	D	E	A	C	Aperture(K*J)
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.