Frequently Asked Questions
Quick solutions for your most frequent questions on products, lead time & service.
What voltage levels of VFDs does SUNSIN supply?
SUNSIN covers low voltage 220V/380V, medium voltage 6kV/10kV and high voltage customized frequency drives for full industrial scenarios.
What industries can your medium & high voltage VFDs be applied to?
Water treatment, marine & offshore, machine tools, mining, oil & gas, commercial HVAC, metallurgy and building materials industries.
What’s the difference between three-level and two-level VFD topology?
Three-level topology outputs lower harmonic distortion, protects marine/CNC precision equipment; two-level is cost-effective for common fan & pump loads.
Can you provide marine-grade anti-corrosion & shockproof VFDs?
Yes, we have MV3000 marine series with salt-fog resistant coating, reinforced anti-vibration structure and full sealed cabinet design.
Do your drives support explosion-proof design for oil & gas fields?
Custom explosion-proof cabinet solutions are available for hazardous oil, gas and mining working environments.
Can your VFD realize constant pressure control for water pumps?
Built-in independent PID constant pressure algorithm, automatic flow adjustment for water supply booster and sewage pump systems.
Is low harmonic design standard for your HV VFDs?
Three-level medium/high voltage VFDs adopt low harmonic topology as standard configuration to avoid interference to instruments and power grid.
Can your machine tool VFD maintain stable low-speed torque?
Machine tool dedicated LV800 series realizes wide constant torque range, eliminates workpiece vibration during ultra-low speed fine machining.
Can SUNSIN design custom integrated drive cabinets?
We provide one-stop integrated cabinet design including circuit layout, heat dissipation, protection and man-machine operation panel.
Can you adjust cabinet protection grade for humid/corrosive sites?
Multiple IP grades optional, sealed anti-corrosion cabinet for sewage, marine and coastal high humidity workshops.
Can we add special communication protocols (Modbus, Profinet) as required?
Support Modbus RTU/TCP, Profinet, CANopen and other mainstream protocols, customized communication modules for BMS and CNC systems.
Is it possible to customize explosion-proof cabinets for oil & gas mining?
Explosion-proof integrated cabinet can be customized to meet Class I hazardous area standards for oilfield and underground mining.
What is your minimum order quantity?
Small trial orders are acceptable for standard low voltage VFDs; medium & high voltage models support single unit sample orders.
How can I get an accurate quotation for VFD solutions?
Send us motor power, voltage, application industry and special technical requirements, our engineer team will issue a formal quotation within 24 hours.
Do you offer OEM & ODM service for inverters and cabinets?
Full OEM & ODM support including private label, customized panel language, firmware logic and cabinet appearance printing.
What payment terms do you support for overseas clients?
T/T, L/C at sight, Western Union and other international payment terms are negotiable for long-term cooperation clients.
What is your standard production lead time?
Stock standard LV VFD:7–10 working days; customized medium/high voltage VFD & cabinet:15–28 working days.
Which shipping methods do you support for global delivery?
Sea freight, air freight, international express and railway transport for different delivery time demands.
Can you deliver goods to my designated seaport or warehouse?
We support FOB, CFR, CIF and DDP terms, deliver to designated port or overseas warehouse as requested.
Do you provide full export customs documents?
Complete set including commercial invoice, packing list, CO certificate, material test report and electrical certification files.
What certifications do your medium & high voltage VFDs have?
CE, ISO9001, marine inspection certificates, fire resistance and explosion-proof related test reports available for project bidding.
Can we arrange factory inspection and on-site technical visit?
Factory tours and production line visits are welcome, our technical engineers can accompany you for product testing and solution communication.
Do you have independent R & D team for new energy converters?
We have a professional R & D team focusing on medium/high voltage topology, marine anti-corrosion and spindle constant torque control technology.
How long is your product warranty period?
Standard 24-month warranty for all VFD products, extended warranty service is optional for large project orders.
Do you provide overseas on-site installation guidance?
We provide remote video technical guidance; overseas on-site engineer service can be arranged for large-scale turnkey projects.
How to get technical support after purchase?
24-hour online sales & technical support via email, WhatsApp and video call for troubleshooting and parameter debugging.
Can you supply spare parts globally after sales?
Global spare parts supply channel, core power modules, control boards and cabinet accessories can be shipped separately worldwide.
What if the VFD fails during the warranty period?
Free replacement of damaged parts or whole unit maintenance under non-human damage conditions within warranty period.
Need More Support?
If you cannot find answers here, contact our professional sales & technical team directly for one-on-one solution consultation.
Contact Us