JMB Lighting Control Transformer 25VA-50kVA 220V/380V

The JMB lighting control transformer is the fixed-installation member of the JMB family. Where the portable version is carried from job to job, this one is bolted into a panel or a distribution board and left to run for years. It works in AC circuits at 50Hz or 60Hz and does two jobs at once: it feeds safety lighting at 12V, 24V or 36V, and it supplies the local control power that machine tools, conveyors and plant equipment need. Industrial and mining customers fit it because one transformer covers both functions, which saves panel space and one line item on the bill of materials. We build it in Yueqing from 25VA up to 50kVA, with high-temperature copper windings and a core that holds its temperature rise under continuous duty.

Key Specifications

What You Get

• JMB lighting control transformer built to your input and output voltage specification
• High-temperature-resistant copper windings for continuous duty
• Terminals clearly marked, wiring diagram printed on the unit
• Panel-mount enclosure with standard fixing centres
• No added waveform distortion – safe for electronic control loads
• Batch test certificate with every order
• 12-month replacement-first warranty

Why Choose This Model

Two things make the JMB worth specifying over a generic control transformer. The first is the safety side: the 12V, 24V and 36V outputs are safety extra-low voltages on an isolated winding, so lighting circuits in wet, conductive or confined locations stay safe without a separate transformer. The second is duty: this transformer is built to run continuously, not intermittently. The windings use high-temperature-resistant copper wire and the core is sized so that temperature rise stays at or below 60 degrees C, even when the panel is closed and the ambient is at the top of the range. It also adds no waveform distortion, which matters more than it used to: modern LED drivers, electronic timers and PLC power supplies are sensitive to what is on the line, and a transformer that clips or rings will make them behave erratically in ways that are very hard to trace back. The JMB covers an unusually wide range, from 25VA for a small indicator circuit right up to 50kVA for plant-wide lighting and control, so once a customer qualifies the series they can standardise on it across a whole site and keep one spare part number in the store. The economics work out better than they first appear, too. Buying one transformer that covers lighting and control instead of two separate units saves the cost of the second device, saves the panel space and the DIN rail it would have occupied, saves the wiring and termination labour, and removes a part number from the spares inventory. On a large panel build those savings add up quickly, and on a maintenance contract they are worth more still, because the store only has to hold one type and every electrician on site already knows how it is wired.

How to Size It

Work out the two loads separately and then add them. Take the total wattage of everything on the safety lighting output, take the total VA of the control devices on the control output, and size the transformer for the sum plus about 20 percent margin. Remember that inductive loads – contactor coils, solenoids, relay banks – draw several times their holding current at switch-on, so a control output that looks like 50VA on paper can demand 150VA for the first few cycles. If you are feeding LED drivers, check their inrush too; some drivers pull hard for the first few milliseconds. Send us the load list and we will size it properly and confirm the temperature rise at your ambient. One practical note from the field: if the panel is sealed and sits in direct sun, the internal ambient can be twenty degrees above the outside air, and that is the number you should size against, not the number on the weather report. We are happy to check a sizing you have already done.

How It Works

The JMB is a double-wound isolating transformer, which means the primary and secondary are separate coils coupled only by the magnetic field in the core. That construction delivers three things the application needs. It steps the voltage down to a safety extra-low level on an isolated winding, so the lighting circuit is not referenced to mains or to earth. It blocks noise, because common-mode interference on the incoming supply has to cross the inter-winding capacitance to reach the secondary, and an earthed screen intercepts most of it on the way. And because the transformer is a linear magnetic device rather than a switched-mode converter, it adds no waveform distortion – the output is a clean sine wave, which is what LED drivers, electronic timers and PLC power supplies are designed to expect. Distortion matters more than it used to. A switching supply that clips or rings on the mains side will make downstream electronics behave erratically in ways that are extremely hard to trace, and the fault always gets blamed on the electronics rather than on the supply. Fitting a transformer that does not distort the waveform removes that whole class of problem from the panel.

Typical Applications

• Machine tool control circuits and work lighting
• Safety lighting in industrial and mining plants
• Indicator lamps and signal circuits on control panels
• Conveyor, packaging and production line control power
• Electronics industry general circuit control supply
• Distribution boards in industrial and mining enterprises

Testing Before Shipment

We test every JMB before it ships. The checks cover turns ratio and output voltage under load, insulation resistance between windings and from each winding to core and frame, continuity of the earthed screen, and a full-load run to confirm the temperature rise stays within the 60 degrees C design limit at the rated ambient. We also confirm the unit behaves correctly at both 50Hz and 60Hz, since the JMB is sold into markets on both frequencies and a core designed for one can run hot on the other. Each order ships with a test report. If your specification calls for dielectric strength testing to a particular standard, type-test data, or specific certification documents, raise it at quotation stage and we will confirm what we can provide.

Ordering, Samples and Shipping

Standard ratings from 25VA to 50kVA are made to order with a 10 pcs minimum on a 15-25 day lead time. To quote we need the input voltage (220V or 380V), the output voltages you need, the capacity in VA, and the quantity. Where a unit feeds both lighting and control loads, send us the load list for each output and we will size them together on one transformer rather than selling you two. Samples are paid by T/T before production and the sample cost is credited against a subsequent production order. Standard shipping is FOB Ningbo or Shanghai.

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