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Electrical and electronics · Industrial automation and drives

Automatic voltage regulator supplier in Bangladesh

Need an automatic voltage regulator supplier in Bangladesh? Tell us whether you need a generator AVR or a mains stabiliser, with the kVA, phase and the voltage range at your board. We source from a verified seller, check the match and deliver.

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Delivered by Roptan

Prefer to deal with suppliers yourself? Post it on the requirement board

Buying automatic voltage regulators in Bangladesh

The name covers two products. A generator AVR measures the alternator's output voltage, compares it with a set point and adjusts the field excitation. A mains stabiliser corrects the supply voltage before it reaches machines. Generator AVRs are usually bought as replacement parts. Stabilisers are bought where supply swings hurt machines, as a Dhaka EPZ factory operator reported in May 2025.

As your automatic voltage regulator supplier in Bangladesh, Roptan first pins down which product you need. We match a generator AVR to the alternator's data, or a stabiliser to the voltage you measure, source from a verified seller, check the papers and deliver. The seller or your generator technician installs and commissions.

Kinds of automatic voltage regulator

PMG-fed generator AVRs

Take excitation power from a permanent-magnet generator on the shaft. This usually isolates the control circuits from non-linear loads, reduces radio interference at the terminals and gives sustained short-circuit current.

Self-excited generator AVRs

Take excitation power from a small part of the generator's own output. For a replacement, give the old AVR's data, so the new unit takes its power the same way.

Servo stabilisers

A motor-driven control selects a tap on an autotransformer or moves a wiper on a variable autotransformer. A dead band stops it hunting. Ask for the response time against the swings at your board.

Static stabilisers

Solid-state switching does the job that relays or a motor do in other designs; thyristor regulators switch on AC half-cycles. There are no moving contacts to wear.

Ferroresonant transformers

Constant-voltage transformers with no active parts. They suppress surges, isolate well, protect against short circuit and can handle input swings of 40 percent or more, but the output is not a pure sine wave.

How to brief an automatic voltage regulator supplier in Bangladesh

Alternator data for a generator AVR: Give the alternator nameplate and the old AVR's sensing voltage, exciter field voltage, current and resistance. An AVR chosen by kVA alone may not match the exciter.
Under-frequency roll-off: The AVR usually cuts voltage in proportion to speed below a set point. On turbocharged engines, a volts-per-hertz slope helps the engine recover after a large load; ask for both set at commissioning.
Parallel running: Say if the set runs in parallel with others. The AVR then needs a droop CT input so the sets share load at the same power factor.
Input window at your board: Mains is nominally three phase at 50 Hz, but measure the lowest and highest voltage at your board over several weeks. The stabiliser's input range must cover both.
Output band and response: State the output accuracy band and the response time your load needs. Higher gain improves accuracy but can make a regulator oscillate or respond slowly.
Loads and expected savings: List the loads, their kVA and phase. A stabiliser does not save energy on every load, so judge it on protection, not on promised savings.

Standards for regulators and alternators

IEC 60034-16-1:2011: Definitions for the excitation systems of synchronous machines. Use its terms for AVR, exciter and PMG so quotes describe the same parts.
ISO 8528-3:2020: Principal characteristics of AC generators for generating sets under the control of their excitation system. ISO 8528-5:2025 is the current edition for the set itself.
IEC 60034-1:2026: Rating and performance of rotating machines, the basis for the alternator the AVR serves. The 2022 edition is withdrawn.

What moves the price of an automatic voltage regulator

kVA rating, and single or three phase, for a mains stabiliser.
Input window: how wide a swing the stabiliser must correct.
Output: the accuracy band and the response time the load needs.
Construction: servo, static or ferroresonant, and whether an isolating design is chosen.
For a generator AVR: PMG-fed or self-excited, and droop input for parallel running.

Lead times and delivery

A generator AVR is a small part that sellers in Dhaka may carry as a spare, while a large stabiliser is usually imported or assembled to order. A replacement AVR can wait on alternator data when the old unit's label is unreadable, so send clear photos early. Roptan confirms dates and any minimum quantity in the quote.

We deliver to your plant or generator room anywhere in Bangladesh. For a generator AVR, the seller or your generator technician fits it, sets the voltage, stability, roll-off and droop, and tests the set on load. For a stabiliser, the seller installs and tests it at your board. You receive the settings, wiring diagram, manual, warranty and a VAT invoice (Mushak 6.3).

What we check for this order

The right productWe check that each quote is for the product you need, a generator AVR or a mains stabiliser.
AVR matches the alternatorWe check sensing voltage, exciter field voltage, current and resistance against the alternator and the old AVR.
Input window covers your boardWe check that the stabiliser's input range covers the lowest and highest voltage you measured at your board.
Datasheet for the unit quotedWe ask for the quoted unit's own datasheet for accuracy, drift and ambient rating, since these figures differ by model.

Questions buyers ask

Does a voltage stabiliser save electricity?

Not on every load. A stabiliser's job is to hold the voltage your machines see inside a band when the supply swings. Ask the seller which of your loads, if any, would use less energy, and judge the purchase mainly on the protection it gives.

Servo or static stabiliser?

A servo stabiliser moves a tap or wiper with a motor, and its dead band stops it hunting. A static stabiliser switches electronically, with no moving contacts. Compare them on the output band, the response time your load can tolerate and the input range at your board.

Can we replace a generator AVR with a different model?

Usually, if it matches the alternator: sensing voltage, exciter field voltage, current and resistance, PMG-fed or self-excited supply, and a droop input if the set runs in parallel. Send the alternator nameplate and photos of the old AVR's label, and the seller confirms the match before you order.

Why does generator voltage drop when a big load starts?

When a large load is switched on, the engine slows. Below a set speed, the AVR usually lowers the voltage in proportion to speed, called under-frequency roll-off, to protect the excitation and help the engine recover. Ask for the knee point and slope to be set at commissioning.

How soon will I hear back about industrial automation and drives?

Within 48 hours of a complete requirement, with a price and a delivery date. A requirement is complete when it has the quantity, where it is needed and by when.

Who do I deal with?

With Roptan, when Roptan manages the order: we buy from the verified seller and deliver to you. With the supplier directly, when you post on the requirement board and choose a quote yourself.