Plating rectifiers and servo stabilizers for electroplating
Deposit thickness is current × time. If the current wanders, the coating varies — and you find out at the salt-spray test, not on the line.
What actually goes wrong
A plating shop has two power problems at once. The rectifier has to hold current precisely across a bath whose resistance changes through the cycle. And the shop atmosphere — acid mist, alkaline vapour, airborne salts — attacks every piece of electrical equipment in the building, including the rectifier that is meant to be controlling the process.
Working in electroplating & surface finishing
What to get right
The decisions on this list are the ones that are expensive to change after the equipment is on site.
Ripple and finish
Under 5% is acceptable for most work; under 2% for bright nickel, chrome and anything where grain structure shows. Above about 10% it is visible in the finish.
Ampere-hour totalising
Chemistry dosing should track the work actually put through the tank. A totaliser on the rectifier does that; an operator’s estimate does not.
Oil cooling in a plating shop
Air cooling pulls the shop atmosphere across the heatsinks and windings. Oil cooled units last substantially longer in a corrosive environment, often regardless of rating.
CED ramp recipes
E-coat needs a defined voltage ramp as the body enters the tank. Stored recipes, switchable from the line PLC, keep it repeatable between operators.
Line voltage stability
A rectifier compensates for input variation up to a point. Beyond it, an upstream stabilizer is what keeps the current setpoint honest.
Busbar losses
At 1000 A a few millivolts of drop across an under-sized or corroded busbar joint is real lost current at the tank. Joints belong on the maintenance schedule.
What we supply into this sector
CED & Plating Rectifier
Low-ripple DC with current control tight enough that deposit thickness repeats across a shift — 50 A to 1000 A at 100 to 300 V, air or oil cooled.
Servo Voltage Stabilizer
5 kVA to 500 kVA, air or oil cooled, correcting to ±1% output. The right first fix when the MIDC feeder swings all day and the equipment keeps tripping on undervoltage.
Isolation Transformer
Galvanic separation between supply and load, with electrostatic shielding that attenuates common-mode noise by 100 dB or better. 1 kVA to 500 kVA.
Automatic Transfer Switch (ATS)
The supply you are on fails, and the load moves to the one that has not — with nobody at the panel. 10 A to 150 A, single phase and three phase.
Through the life of the machine
Questions we get asked
Anything not covered here, call us — most of it is faster to answer on the phone.
01What rectifier ripple do I need for bright nickel plating?
Under 2%. Bright nickel and decorative chrome show ripple in the deposit grain structure and the finish comes out dull or streaked. Our filtered option holds under 2%; the standard build is under 5%, which is fine for zinc and general functional plating.
02Should a plating rectifier be air cooled or oil cooled?
In a plating shop, usually oil cooled whatever the rating. Air cooling draws acid mist and alkaline vapour straight across the heatsinks and windings, and the corrosion shortens life considerably. The environment decides this more than the rating does.
03Why does rectifier ripple matter in plating?
Because the deposit follows the current. Excess ripple means the plating current is not steady, and that shows up as variation in deposit thickness, brightness and adhesion across a batch — the kind of defect that is only found at inspection, after the work is done. Ripple limits differ by process and by bath chemistry, so the figure to design to is the one your process specifies, not a general one.
04Should a plating rectifier run constant current or constant voltage?
Most plating is current-driven, because deposit thickness follows amp-hours through the bath. Constant current holds the deposition rate steady as the bath’s resistance changes with temperature, concentration and the area of work loaded. Constant voltage has its uses — some anodising and CED sequences are voltage-ramped by specification. If your process sheet gives a voltage profile, the rectifier needs to follow it, so tell us which at enquiry.
05How is a rectifier sized for a plating line?
From current density and total work area, not from the tank size. Multiply the area to be plated by the process current density to get amps, then set the voltage from the bath resistance and the anode-cathode spacing, with headroom for the largest jig you intend to run. Sizing from the biggest tank you own tends to buy far more rectifier than the work needs.
06Can one rectifier feed more than one tank?
Only where the tanks genuinely share a process and never run different recipes at once, and even then it constrains you. Each bath draws its own current and reaches its endpoint at its own time; a shared rectifier means they finish together whether the work is ready or not. For a line running mixed work, separate units per tank cost more initially and are usually cheaper in scrap.
We will do the load grading with you
Site survey, load list and a single-line diagram before anything is quoted. That is where the specification is actually decided.