: +86 18620275879      Edgar@bedford.com.cn

Hot-Selling Products

Share to:


The B503D general purpose vector inverter adopts DSP control system, completely speed sensorless vector control, compared with V/F control, vector control has greater superiority, embedded PG-free vector control (SVC), V/F control all in one. The B503D series also has 4 programmable digital inputs, 1 relay output, 10 relay output options, 1 analogue output, 8 speed control functions and 22 terminal function options.superiority, embedded PG-free vector control (SVC), V/F control all in one. The B503D series also has 4 programmable digital inputs, 1 relay output, 10 relay output options, 1 analogue output, 8 speed control functions and 22 terminal function options.

Product description

B503D series frequency control universal vector controller.


Programmable digital input: 4 digital input terminals

Programmable analog input: AI1:0~10V input, AI2:0~10V or 4~20mA input

Open collector output: 1 output

Relay output: 1 output

Analog output: 1 output, 0/4~20mA or 0~10V can be selected respectively

Product advantages

• Frequency setting method: digital setting, analog setting, serial communication setting, multi-speed, PID setting, etc.

• PID control function

• Multi-stage speed control function: 8-stage speed control

• Instantaneous power failure non-stop function

• Speed tracking and restart function: realize smooth start without impact on the rotating motor

• Key function: user-defined multi-function shortcut keys

• Automatic voltage adjustment function: when the grid voltage changes, it can automatically keep the output voltage constant

• Provides as many as 25 fault protection functions: overcurrent, overvoltage, undervoltage, overtemperature, phase loss, overload and other protection functions

Product parameters

Input voltage range:380/220V±15%

Input frequency range:47~63Hz

Output voltage range:0~Rated input voltage

Output frequency range:0~600Hz


Size of 0.75~15KW model                          Size of 18.5~110KW model

Size of 132-315KW model (with and without pedestal)

Size of 350~630KW model

Company Contact

Guangzhou Bedford Electrical Equipment Co., Ltd.

Address: 1st Floor Building C, No.2, Taowan Industry Zone, Liwan District, Guangzhou, China.

Phone: +86 20-81561021

Fax: +86 20-81891390

Zip code: 510370

Service Hotline: 1350002099 18664751963

Email: bedford.cn@gmail.com


In order to ensure the safe operation of the inverter, the work must be carried out by certified and qualified electricians.

It is prohibited to use high-voltage insulation testing equipment to test the insulation of the cables connected to the inverter.

Even if the inverter is not in operation, other power input wires, DC circuit terminals and motor terminals may still carry dangerous voltages. Therefore, after disconnecting the switch, you must wait for 5 minutes to ensure that the inverter is discharged before starting work.

The ground terminal of the inverter must be reliably grounded

200V class grounding resistance is 100Ω or less

400V class grounding resistance is 10Ω or less

660V class grounding resistance is 5Ω or less

Otherwise, there is a risk of electric shock and fire.

Do not connect the input terminal (R.S.T) and output terminal (U.V.W) of the inverter to the ground wrong, otherwise it will cause internal damage to the inverter.

It is forbidden to wire and operate the inverter with wet hands, otherwise there is a danger of electric shock.


The following faults may be encountered during the use of the inverter. Please refer to the following methods for simple fault analysis:

No display after power-on:

1. Use a multimeter to check whether the input power of the controller is consistent with the rated voltage of the controller. If there is a problem with the power supply, please check and eliminate it.

2. Check whether the CHARGE lamp is on. If this light is on, the fault may be in the switching power supply. Please seek service.

After power on, the power air switch trips:

1. Check whether there is a grounding or short circuit between the input power

supplies and eliminate the problem.

2. Check whether the rectifier bridge has been broken down, if it is damaged, seek service.

The motor does not rotate after the controller is running

1. Check whether there is a balanced three-phase output among U, V, and W. If there is, the motor circuit or itself is damaged, or the motor is blocked due to mechanical reasons. Please exclude.

2. There is output but the three phases are not balanced. It may be because the

controller driver board or output module is damaged, please seek service.

3. If there is no output voltage, the drive board or output module may be damaged, please seek service.

Power on the controller shows normal, after running, the power air switch tripped:

1. Check whether there is a short circuit between the output modules. If yes, please seek service.

2. Check whether there is a short circuit or grounding between the motor leads. If so, please exclude it.

3. If the trip occurs occasionally and the distance between the motor and the controller is relatively long, consider adding an output AC reactor.

After-sales service

1. The warranty is limited to the inverter itself. Within 12 months from the date of purchase, the inverter will provide free maintenance services if the product is damaged due to malfunctions caused by the product itself within 12 months from the date of purchase.

2. During the warranty period, if something happens, our company will charge a certain amount of maintenance fee depending on the situation.

A. Failure to strictly follow the "Instruction Manual" or exceed the standard requirements in an environment that does not meet the requirements of the "Instruction Manual".

B. Failure caused by self-repair or modification without permission.

C. Faults caused when the inverter is used for abnormal functions.

D. The inverter is damaged due to incorrect wiring.

E. Damage caused by improper storage, fall or other external factors after purchase.

F. Failures caused by natural disasters such as abnormal voltage, lightning, fire, water mist, metal dust, gas corrosion, earthquakes, storms, or disaster-related causes.

G. Tear off the product identification (such as nameplate, etc.) without authorization; the serial number of the body does not match the warranty card.

3. If you have any questions, please contact the agent or contact our company directly.

4. For machines beyond the warranty period, our company will also provide lifetime paid maintenance services.

About us

Bedford water supply equipment is widely used in high-rise residential buildings, villas, schools, hospitals, large communities, air source heat pump hot and cold water systems, solar water heating systems, water treatment, energy-saving water supply systems for buildings, and other occasions. ​​​​​​​

Subscribe to receive the latest news.
Copyright @ 2021 Guangzhou Bedford Electric Equipment Co.,Limited.
Contact us

help us respond to you timely